14th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems

Transcription

1 14th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems 1 st - 4 th September, 2015 IAEA Headquarters, Vienna International Centre Vienna, Austria Venue: M Building, Board Room A IAEA Scientific Secretary R. Kamendje International Atomic Energy Agency Vienna International Centre Wagramer Straße 5 PO Box 100 A-1400 Vienna, Austria NAPC Physics Section Tel: Fax: Physics@iaea.org International Programme Advisory Committee Chair: S. Pinches (ITER) H. Berk (USA), C. Hellesen (Sweden), A. Fasoli (Switzerland), Ph. Lauber (Germany), W. Heidbrink (USA), S. Sharapov (UK), G.Vlad (Italy), K. Shinohara (Japan), M.Osakabe (Japan), E. Frederickson (USA), X. Ding (China) Local Organisation Committee Secretariat: L. Hedervari Contact address: physics@iaea.org Meeting Website: TM49508.html 1

2 Topics I. Alpha Particles Physics II. Transport of Energetic Particles III. Effects of Energetic Particles in Magnetic Confinement Fusion Devices IV. Collective Phenomena: Alfvén Eigenmodes, Energetic Particle modes and Others. V. Runaway Electrons and Disruption VI. Diagnostics for Energetic Particles 2

3 Schedule Invited Orals (I) are allotted 30 min + 10 min for discussion. Regular Orals (O) are allotted 20 min + 5 min for discussion. Tuesday, 1 st September Opening Remarks R. Kamendje Session 1 Transport of energetic Particles I Chair: S. Pinches :15 I-1: P. Schneider Overview of diagnostic enhancements and physics studies of confined fast-ions in ASDEX Upgrade O-1: M. Podesta Effects of fast ion phase space modifications by instabilities on fast ion modeling Coffee Break (Photo) Session Transport of Energetic Particles II Chair: Y. Kolesnichenko I-2: I. Furno Non-diffusive transport of suprathermal ions in toroidally magnetized plasmas O-2: C. Hopf Recent progress in neutral beam current drive experiments on ASDEX Upgrade O-3: R. Waltz Development and validation of a critical gradient energetic particle driven Alfven eigenmode transport model for DIII-D tilted neutral beam experiments Lunch Break Session 3 Transport of energetic Particles III Chair: A. Fasoli I-3: W. Heidbrink Experimental determination of the threshold for stiff fast-ion transport by Alfven eigenmodes O-4: C.Collins Measurements of Alfven eigenmode induced fast-ion transport in DIII-D O-5: J. Rasmussen Investigating fast-ion transport due to sawtooth crashes using Collective Thomson Scattering 3

4 Coffee Break Session 4 Transport of energetic Particles IV Chair: K.Shinohara I-4: D. Pfefferle Alpha particle confinement in the European DEMO O-6: N. Gorelenkov Validating predictive models for fast ion profile relaxation in burning plasmas O-7: N. Bolte Measurement and Simulation of Deuterium Balmer-Alpha Emission from First- Orbit Fast Ions and the Application to General Fast-Ion Loss Detection in the DIII-D Tokamak Adjourn 4

5 Wednesday, 2 nd September Session Energetic particles in magnetic confinement fusion devices Chair: M. Hole I-5: M. Schneider Modelling 3rd harmonic Ion Cyclotron acceleration of D beam for JET Fusion Product Studies O-8: M. Schneller Nonlinear Energetic Particle Transport in the Presence of Multiple Alfvenic Waves in ITER O-9: J. Kim Experimental Observations of Fast-ion Losses on KSTAR Coffee Break Session Energetic particles and collective phenomena 1 Chair: Y. Todo I-6: G. Fu Stability and Nonlinear Dynamics of Beam-driven Instabilities in NSTX O-10: M. Hole The impact of anisotropy and flow on magnetic configuration, and stability O-11: P. Rodrigues Sensitivity of alpha-particle driven Alfven eigenmodes to q-profile variation in ITER scenarios Lunch Break Session Energetic particles and collective phenomena 2 Chair: H. Berk I-7: A. Biancalani Non-perturbative nonlinear interplay of Alfven modes and energetic ions O-12: F. Nabais Observation of chirping modes in JET at frequencies above the Alfven frequency Coffee Break Poster Session Adjourn Meeting Dinner 5

6 Thursday, 3 rd September Session Energetic particles and collective phenomena III Chair: C. Hellesen I-8: Y. Kazakov Fast Ion Generation with Novel Three-Ion ICRF Scenarios: from JET, W7-X and ITER applications to aneutronic fusion studies O-13: L. Horváth Experimental investigation of the radial structure of energetic particle driven modes O-14: W. Zhang Verification and Validation of Gyrokinetic Particle Simulation of Fast Electron Driven beta-induced Alfven Eigenmode on HL-2A Tokamak Coffee Break Session Collective phenomena: Alfvén eigenmodes, energetic particle modes and others I Chair: S. Sharapov I-9: X. Wang Structure of wave-particle interactions in nonlinear Alfvenic fluctuation dynamics O-15: S. Tripathi Excitation of waves by a spiraling ion beam in a large magnetized plasma O-16: D. Spong Analysis of energetic particle driven Alfven instabilities in 3D toroidal systems using a global gyrokinetic Lunch Break Session Collective phenomena: Alfvén eigenmodes, energetic particle modes and others II Chair: W. Heidbrink I-10: A. Bierwage Alfven Acoustic Channel for Ion Energy in High-Beta Tokamak Plasmas O-17: M. Garcia-Munoz Impact of localized ECRH on NBI and ICRH driven Alfven eigenmodes in the ASDEX Upgrade tokamak Coffee Break Poster Session Adjourn 6

7 Friday, 4 th September Session Collective phenomena: Alfvén eigenmodes, energetic particle modes and others III Chair: G. Vlad I-11: M. Fitzgerald Predictive nonlinear studies of TAE-induced alpha-particle transport in the Q=10 ITER baseline scenario O-18: A. Melnikov The study of NBI-driven chirping mode properties and radial location by Heavy Ion Beam Probe in the TJII stellarator Coffee Break Session Collective phenomena: Alfvén eigenmodes, energetic particle modes and others IV Chair: Ph. Lauber I-12: M. Cole Progress in non-linear electromagnetic gyrokinetic simulations of Toroidal Alfven Eigenmodes O-19: Y. Todo Simulation study of profile stiffness of fast ions interacting with multiple Alfven eigenmodes O-20: M. Van Zeeland Impact of Localized Electron Cyclotron Heating on Alfven Eigenmodes in DIII-D Lunch Break Session Collective phenomena and runaway electrons Chair: M. Porkolab O-21: G. Papp Coupled kinetic-fluid simulation of runaway electron dynamics O-22: Z. Chen Study of disruption generated runaway electrons on J-TEXT tokamak Coffee Break Session Summaries Chair: S. Pinches S-1: H. Berk Summary of theory presentations S-2: M. Garcia-Munoz Summary of experimental presentations R. Kamendje Closing Remarks End of Meeting 7

8 List of Invited Orals: I-1 P. Schneider Overview of diagnostic enhancements and physics studies of confined fast-ions in ASDEX Upgrade I-2 I. Furno Non-diffusive transport of suprathermal ions in toroidally magnetized plasmas I-3 W. Heidbrink Experimental determination of the threshold for stiff fast-ion transport by Alfven eigenmodes I-4 D. Pfefferle Alpha particle confinement in the European DEMO I-5 M. Schneider M Schneider, Modelling 3rd harmonic Ion Cyclotron acceleration of D beam for JET Fusion Product Studies I-6 G. Fu Stability and Nonlinear Dynamics of Beam-driven Instabilities in NSTX I-7 A. Biancalani Non-perturbative nonlinear interplay of Alfven modes and energetic ions I-8 Y. Kazakov Fast Ion Generation with Novel Three- Ion ICFR Scenarios: from JET, W7-X an ITER applications to aneutronic fusion studies. I-9 X. Wang Structure of wave-particle interactions in nonlinear Alfvenic fluctuation dynamics I-10 A. Bierwage Alfven Acoustic Channel for Ion Energy in High-Beta Tokamak Plasmas I-11 M Fitzgerald Predictive nonlinear studies of TAE-induced alphaparticle transport in the Q=10 ITER baseline scenario I-12 M. Cole Progress in non-linear electromagnetic gyrokinetic simulations of Toroidal Alfven Eigenmodes 8

9 I-1: overview of diagnostic enhancements and physics studies of confined fast-ions in asdex upgrade P. A. Schneider 1,*, B. Geiger 1, S. K. Nielsen 2, G. Tardini 1, M. Weiland 1, S. Äkäslompolo 3, A. S. Jacobsen 2, F. Ryter 1, M. Salewski 2, the ASDEX Upgrade Team 1 and the EUROfusion MST1 Team 4 1 Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, Garching, Germany 2 Technical University of Denmark, Department of Physics, Dk-2800 Kgs. Lyngby, Denmark 3 Aalto University, Finland 4 *philip.schneider@ipp.mpg.de, At the ASDEX Upgrade (AUG) tokamak the capabilities to diagnose confined fast particles were successively enhanced over the past years. These include the collective Thomson scattering (CTS), the fast-ion D-alpha (FIDA) diagnostic, the neutral particle analysers (NPA) and the neutron spectrometer. The CTS was upgraded with an additional receiver for continuous background measurements. To extend the coverage of the fast-ion velocity space, the FIDA diagnostic was upgraded from 3 to 5 optical arrays. Red- and blueshifted parts of the FIDA radiation are measured simultaneously with a new spectrometer setup. While FIDA and CTS have a good radial resolution, the measured signal is integrated over a range in energy and pitch. Direct energy and pitch resolved measurements of the central fast-ion content are obtained with a new active NPA. This NPA uses a compact solid state detector and is focused on the same heating beam as the FIDA diagnostic for the active signal. To investigate fast edge localised phenomena, the data acquisition system of the passive E,B-NPAs was upgraded. A neutron spectrometer measures the neutron energy distribution resulting from D-D fusion reactions, thus providing an independent diagnostic tool. The standard tool to interpret FIDA and NPA measurements is a parallel version of the FIDASIM code. The run time for simulations of all channels is below 30 min for one time point. An overview of recent results obtained with the improved set of diagnostics will be presented. The measured impact of MHD instabilities such as ELMs and sawteeth on fast-ion confinement will be discussed. The measured fast-ion redistribution due to sawteeth matches predictions based on the Kadomtsev model very well. Information on the 2D fast-ion velocity space is obtained with tomographic reconstructions using multiple FIDA views. The acceleration of neutral beam injected deuterons by the 2nd harmonic ICRF heating was confirmed with all fast-ion diagnostics and can be modeled using an RF kick operator in TORIC or TRANSP. The radial fast-ion transport is investigated for on- and off-axis heating and the measurements are compared with different transport models. Neoclassical transport can be sufficient to explain the measurements in some cases, but when an anomalous contribution to the fastion diffusivity is required to better match the observations, its value is typically below 1 m 2 /s. 9

10 I-2: non-diffusive transport of suprathermal ions in toroidally magnetized plasmas I. Furno, A. Bovet, A. Fasoli, K. Gustafson and P. Ricci Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, CH-1015 Lausanne, Switzerland The interaction between small scale turbulence and suprathermal ions is still an open question for burning plasmas in next generation fusion devices, such as in DEMO, in which suprathermal ions will be injected by ICRH, NBI and generated by fusion reactions. As suprathermal ions will be responsible for a large fraction of plasma heating and non-inductive current drive, understanding turbulent transport across the magnetic field is of fundamental importance. Experimental data are required to compare and validate the relevant theoretical and numerical models. In this contributions, we report on recent experimental, numerical and theoretical studies in the laboratory device TORPEX, which permits full characterization of suprathermal ion transport and turbulent structures. TORPEX is a simple magnetized toroidal device in which, similarly to the Scrape-Off Layer of fusion devices, field-aligned blobs are intermittently generated and propagate across the confining magnetic. Suprathermal ions are injected in turbulent TORPEX plasmas using a miniaturized source and detected using gridded-energy analyzers. Combining uniquely resolved three-dimensional measurements and first-principle numerical simulations, we present first unambiguous evidence for sub-diffusive and superdiffusive suprathermal ion transport regimes. We show that the transport character is determined by the interaction of the suprathermal ion orbits with intermittent blobs, and is strongly affected by the ratio of the suprathermal ion energy to the background plasma temperature. These results confirm the importance of orbit gyroavering in mitigating the suprathermal ion turbulent transport. Using conditional sampling we obtain time-resolved measurements of the cross-field dynamics of the suprathermal ions, for the first time. Suprathermal ions interacting with radially propagating blobs experience super-diffusive transport, which is associated with intermittent displacement events of the ion beam. This work was supported in part by the Fonds National Suisse de la Recherche Scientifique. 10

11 I-3: experimental determination of the threshold for stiff fast-ion transport by alfvén eigenmodes W. W. Heidbrink 1, C.S. Collins 1, D.C. Pace 2, C.C. Petty 2, L. Stagner 1, M.A. Van Zeeland 2, Y.B. Zhu 1 1 University of California Irvine, Irvine, CA, USA 2 General Atomics, San Diego, CA, USA Three separate DIII-D experiments suggest critical threshold-like behavior for fast-ion transport in the presence of many, small-amplitude Alfvén eigenmodes (AE). During the current ramp, although the amplitude of AE activity is largest for peaked beam deposition profiles, the measured fast-ion profile is nearly identical [1]. Similarly, in steady-state scenario plasmas, fastion transport is large in plasmas with many AEs but nearly classical in plasmas with few AEs [2,3]. Recent experiments concentrate on accurate determination of the threshold for appreciable transport. Modulation of one beam source permits measurement of the incremental fast-ion transport vs. AE amplitude. The AE amplitude is varied by scanning the average beam and electron cyclotron heating power. Neutral-particle analyzer (Fig. 1), fast-ion D α (FIDA), neutron, and scintillator loss detector diagnostics all detect a rise in transport above a certain phase-space dependent AE amplitude threshold. The FIDA data indicate that the peak of the modulated fast-ion flux occurs at normalized minor radii of ρ= , corresponding to the radial location of AEs. Fig.1. As the average injected beam power increases, the amplitude of AE activity increases until, above a threshold, the modulated fast-ion flux suddenly increases. These experiments are guiding development of critical gradient models that can predict alpha profiles in future devices. The threshold for appreciable transport is one key issue. The data show that a threshold based on marginal AE stability is too pessimistic. Initial analysis [3] suggests that the onset of stochasticity due to island overlap is necessary. Another hypothesis under investigation is that stiff critical gradient transport results only when the AE growth rate exceeds the ion temperature gradient mode rate at the same low toroidal mode number. References [1] Heidbrink W.W. et al, Nucl. Fusion 53, (2013). [2] Heidbrink W.W. et al, Plasma Phys. Control. Fusion 56, (2014). [3] Holcomb C.T. et al, Phys. Plasmas (2015), submitted. 11

12 I-4 alpha particle confinement in the european demo D. Pfefferlé, H. W. Patten, S. Lanthaler, W. A. Cooper, J. P. Graves, and A. Fasoli École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne, Switzerland Energetic ions arise in fusion plasmas from heating systems such as ICRH, NBI and fusion reactions. Their transport can be significantly enhanced in the presence of non-axisymmetric deformations and 3D internal structures, for example due to magnetic field ripple, external perturbations or MHD activity. Energetic ions, by drifting away from field-lines, are more affected by non-axisymmetric components than thermal particles; non conservation of toroidal momentum and large drift orbits leads to enhanced collisionless losses. The VENUS-LEVIS orbit solver is designed to investigate supra-thermal particle transport in the presence of general 3D fields. The code combines flexibility in the choice of coordinate system with a strict Hamiltonian formulation of second-order guiding-centre and full-orbit equations, switching between the two in the event of strong field variation (gradient, curvature and torsion). Second-order terms, such as the Baňos drift, are important to reproduce matching particle and guiding-centre trajectories. Confinement of alpha particles in the European DEMO reference design is assessed, focusing on the effect of magnetic ripple caused by the finite number of toroidal coils. 3D MHD equilibria, with nested ux-surfaces and a single magnetic axis, are computed within the VMEC code. These nonlinear solutions to the MHD force balance, obtained via the Kruskal-Kulsrud energy minimisation principle, conveniently describe tokamak saturated plasma states. This equilibrium approach is compared with a perturbed vacuum field approach, where deviations from axisymmetry are simply added to a 2D equilibrium and the plasma response is neglected. 12

13 I-5: modelling 3 rd harmonic ion cyclotron acceleration of d beam for jet fusion product studies experiments M. Schneider 1, T. Johnson 2, S. Sharapov 3, T. Hellsten 2, R. Dumont 1, M. Mantsinen 4,5, M. Nocente 6, J. Eriksson 7, V. Kiptily 3, J.-B. Girardo 1 and JET contributors* EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK;1CEA, IRFM, F Saint- Paul-lez-Durance, France; 2 Ass. Euratom-VR, KTH, Stockholm, Sweden; 3 CCFE, Culham Science Centre, Abingdon, OX14 3D, UK; 4 Catalan Institution for Research and Advanced Studies, Barcelona, Spain; 5 Barcelona Supercomp. Center, Barcelona, Spain ; 6 Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano- Bicocca, Milano, Italy; 7 Dept. of Physics & Astronomy, Uppsala Univ., Sweden Fusion products will play a crucial role in future tokamak fusion devices: alpha particles are mainly aimed at sustaining fusion reactions and reach the ignition, while other fusion products are also used for diagnostic purposes. For this reason it is essential to fully understand their behaviour in present day tokamaks. To this prospect, 2014 JET fusion product studies experiments were based on ICRH 3rd harmonic heating of D beams in order to generate a MeV range D tail to enhance D-D and D-He3 fusion reactions and study confined and lost fusion products with dedicated diagnostics and modelling tools. These experiments have demonstrated a clear production of fast ion D tail, visible from neutron [1] and gamma-ray [2] diagnostics. Proper modelling is required to ensure the correct interpretation of these data and to go beyond actual measurements by simulating the ion dynamics with time-evolving power references. SPOT [3] is an orbit following Monte Carlo code recently extended with the RFOF [4] library for simulating the interaction between ions and ICRF waves in the context of the quasilinear theory. The SPOT/RFOF package has been run in association with the EVE full wave code for ICRF heating [5], and the NEMO beam deposition code [6] to simulate the relevant discharges including the NBI+ICRH synergy. A comparison of the ion distribution and high energy cut off between the SPOT/RFOF code and the neutron and gamma-ray spectroscopy is presented, showing an overall good agreement. Diagnostic sensitivity according to their line of sight is explored. PION [7] and SELFO-light [8] simulations are also included for comparison. In addition, the fast D tail decay/sustainment when switching off NBI and ICRF heating sources is presented. The ICRF heating efficiency according to the geometry of the beam injecting Positive Ions Neutral Injectors (PINIs) is analysed. Finally, a sawtooth activity has been observed in some discharges, which has been interpreted using SPOT/RFOF simulations in the framework of Porcelli s theoretical model: NBI+ICRH accelerated ions have a strong stabilizing effect, yet sawtooth crashes occur, due in particular to tornado modes induced by fast ions [9]. [1] M. Gatu Johnson et al, Nuc. Instr. Meth. A (2008) [2] V. G. Kiptily, et al, NF 42, 999 (2002) [3] M. Schneider et al, PPCF 47, 2087 (2005) [4] T. Johnson et al, AIP Proc. 1406, 373 (2011) [5] R. Dumont et al, NF 53, (2013) [6] M. Schneider et al, NF 51, (2011) [7] L.-G. Eriksson et al, NF 33,1037 (1993) [8] T. Hellsten et al, NF (2013) [9] J.-B. Girardo et al, to be submitted to PP. * See the Appendix of F. Romanelli et al.,proceedings of the 25th IAEA Fusion EnergyConference 2014, Saint Petersburg, Russia 2. 13

14 I-6: stability and nonlinear dynamics of beam-driven instabilities in nstx G. Y. Fu 1, F. Wang 1, D.Y. Liu 2, E. D. Fredrickson 1, M. Podesta 1 1 Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA 2 University of California, Irvine, California 92697, USA Address of Submitting Author: fu@pppl.gov Energetic particle modes and Alfvénic modes driven by super-alfvénic beam ions were routinely observed in neutral beam heated plasmas on the National Spherical Torus Experiment (NSTX). These modes can significantly impact beam-ion transport, thus causing beam-ion redistribution and losses. Recent simulation results with the kinetic/mhd hybrid code M3D-K show excitation and nonlinear saturation of n=1 fishbone with strong frequency chirping and beam ion radial profile flattening [1]. The simulation results of TAEs show mode radial structure consistent with the reflectometer measurements of electron density fluctuations [2]. In this paper we report on new self-consistent simulations of both fishbone instability and TAEs in NSTX plasmas. Our model is self-consistent with mode structure determined non-perturbatively including effects of energetic particles and plasma toroidal rotation. First, the stability of the n=1 fishbone is systematically calculated with effects of plasma toroidal rotation for weakly reversed shear q profiles with minimum safety factor above unity. It is found that a new instability region appears for q min > 1.35 when rotation is included. The corresponding fishbone mode structure has strong ballooning feature. In contrast, the fishbone with q min < 1.35 has a dominant m/n=1/1 kink structure. Nonlinear simulation shows strong mode frequency chirping as beam ions are redistributed. Second, NSTX experimental results show that multiple low-amplitude beam-driven TAEs with weak frequency chirping can transit to mode avalanche with much larger amplitudes and strong frequency chirping. In order to explore mechanisms of avalanche, M3D-K nonlinear simulations of multiple beam-driven TAEs and the n=1 fishbone have been carried out for the first time. The simulation results show strong interaction between TAEs and fishbone that either enhances or reduces saturation level of individual modes depending on mode number and other parameters. As beam ion beta increases beyond stability threshold, mode saturation levels are found to increases sharply. When beam ion beta exceeds some critical value, the locally flattening regions merge together resulting in global particle transport and substantial particle loss. These results are similar to the TAE avalanche observed in NSTX. [1] F. Wang et al, Phys. Plasmas 20, (2013) [2] D. Liu et al, Phys. Plasmas 22, (2015) 14

15 I-7: non-perturbative nonlinear interplay of alfvén modes and energetic ions. A. Biancalani 1, A. Bottino 1, Ph. W. Lauber 1, B. Scott 1, A. Mishchenko 2, A. Koenies 2, C. Di Troia 3, F. Zonca 3,4 1 Max-Planck-Institut für Plasmaphysik, Garching, Germany. 2 Max-Planck-Institut für Plasmaphysik, Greifswald, Germany. 3 ENEA C. R. Frascati - C. P Frascati, Italy. 4 Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou, PRC. Numerical simulation results of Alfvén modes driven unstable by supra-thermal ions in tokamaks are presented. The global nonlinear gyrokinetic particle-in-cell code NEMORB is used for such studies. The mode structure is analyzed in the linear and in the nonlinear phase; and, thereby, the self-consistent (nonlinear) interplay of mode structure and energetic particle transport is systematically investigated and explained. In particular, both wave-particle and wave-wave nonlinearities are considered and the regimes where either one is dominant are identified by varying the linear instability drive. Various aspects of the nonlinear dynamics are addressed separately, by artificially switching off other nonlinearities. Thus, also the effect of nonlinear modification of the mode frequency is investigated. Finite-Larmor-radius effects of energetic ions on mode structure, frequency and growth rate are also described. The insights into the isolated nonlinear dynamics are then used to interpret results of fully non-perturbative nonlinear simulations. Acknowledgements: This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect those of the European Commission. Simulations were performed on the IFERC-CSC Helios supercomputer within the framework of the ORBFAST project. This work has been done in the framework of the nonlinear energetic particle dynamics (NLED) European Enabling Research Project (EUROFUSION WP15-ER- 01/ENEA-03). 15

16 I-8: fast ion generation with novel three-ion icfr scenarios: from jet, w7-x and iter applications to aneutronic fusion studies Ye.O. Kazakov 1, D. Van Eester 1, J. Ongena 1, R. Bilato 2, R. Dumont 3, E. Lerche 1, A. Messiaen 1 1 Laboratory for Plasma Physics, LPP-ERM/KMS, Brussels, Belgium 2 Max-Planck-Institut für Plasmaphysik, Garching, Germany 3 CEA, IRFM, F Saint-Paul-lez-Durance, France Address of Submitting Author: yevgen.kazakov@rma.ac.be Plasma heating with waves in the ion cyclotron range of frequencies (ICRF) is widely used in fusion research. In addition to plasma heating itself, ICRF has a number of important supplementary applications, including the generation of high energy ions. This is typically needed for fusion product studies, when RF heating is applied to accelerate a small group of resonant ions to very high energies [1]. Such particles mimic fusion-born alphas and this provides a tool to study fast ion dynamics and to check and optimize the quality of plasma confinement. This is the main function of the ICRF system in the Wendelstein 7-X project. In present-day fusion devices, ICRF minority heating normally uses concentrations of resonant ions of about 5%, resulting in tail energies of a few hundred kev. MeV-range particles are typically generated with a combination of NBI and second or third harmonic ICRF heating [2]. Recently, we have identified a new set of ICRF scenarios, which likewise minority heating rely on fundamental (N = 1) ion cyclotron absorption, and thus NBI pre-heating is not such essential as for the harmonic ICRF scenarios. A distinct feature of the three-ion ICRF scenarios is the high efficiency of RF power absorption at very low resonant ion concentrations (~ 1% and even below) [3]. This is possible because of the improved wave polarization in the absorption region. As a result, the absorbed power per resonant particle is much higher than for the traditional two-ion minority heating scenarios and resonant ions can be accelerated to MeV energies with ICRF. We review possible applications of the proposed method for the generation of high energy ions in fusion plasmas. Three-ion ICRF scenarios are particularly relevant for future fusion machines, e.g. W7-X and ITER, where significantly higher plasma densities will be used for operation. We also discuss the relevance of the proposed heating scenarios for aneutronic fusion reaction studies p + 11 B 3α MeV. As follows from Fig. 1, a very efficient absorption of ICRF power by a small fraction of boron ions is possible in a hydrogen-tritium mixture H:T 85%:15%.This can be used for the acceleration of boron ions to MeV energies, where the cross-section of the proton-boron fusion reaction has a maximum. Fig.1. ICFR power absorption efficiency by boron ions in T-hydrogen plasmas [1] S.E. Sharapov et al., Fast Ion D-D and D-3He Fusion on JET, this conference. [2] M.J. Mantsinen et al., Analysis of ICRF heating and ICRF-driven fast ions in recent JET experiments, this conference. [3] Ye.O. Kazakov, D. Van Eester, R. Dumont and J. Ongena, Nucl. Fusion (2015). 16

17 I-9: structure of wave-particle interactions in nonlinear alfvénic fluctuation dynamics* X. Wang 1, S. Briguglio 2, G. Fogaccia 2, Ph. Lauber 1, M. Schneller 1, G. Vlad 2, F. Zonca 2 1 Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, Garching D-85748, Germany. 2 ENEA for EUROfusion, Via E. Fermi 45, Frascati, Italy Emai Address of Submitting Author: xin.wang@ipp.mpg.de Recent theoretical [1, 2] and numerical simulation studies [3, 4] show that non-adiabatic frequency chirping and phase locking of Alfvén waves lead to meso- and macro-scale transport of resonant particles. The interplay between mode structure and resonant particles is crucial for understanding the nonlinear dynamics of such waves excited by energetic particles (EP) in fusion plasmas. In our work, these dynamics are investigated by means of the nonlinear hybrid magnetohydrodynamics gyrokinetic code (XHMGC) [5, 6] with particular emphasis on beta induced Alfvén eigenmodes (BAE), which have been observed in fusion experiments and can generate significant EP transport [7]. Nonlinear dynamics are investigated, ranging from marginal stability to strongly driven regimes. Phase space zonal structures (PSZS) [2] are analyzed using phase space numerical diagnostics based on the Hamiltonian mapping [4]; demonstrating that nonperturbative EP response and finite radial structures of fluctuations in nonuniform plasmas become increasingly more important for increasing EP drive. [1] F. Zonca et al., Plasmas Phys. Control. Fusion 57, (2015) [2] F. Zonca et al., New J. Phys. 17, (2015) [3] G. Vlad et al., Nucl. Fusion 53, (2013) [4] S. Briguglio et al., Phy. Plasmas 21, (2014) [5] S. Briguglio et al., Phys. Plasmas 2, 3711 (1995). [6] X. Wang et al., Phys. Plasmas 18, (2011). [7] Ph. Lauber et al., Plasmas Phys. Control. Fusion 51, (2009). [8] Ph. Lauber et al., J. Comp. Phys., 226(1) 447 (2007) This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect thoseof the European Commission. 17

18 I-10: alfvén acoustic ahannel for ion energy in high - beta tokamak plasmas A. Bierwage 1, N. Aiba 1, K. Shinohara 2, M. Yagi 1 1 Japan Atomic Energy Agency, Rokkasho Fusion Institute, Aomori, Japan 2 Japan Atomic Energy Agency, Naka Fusion Institute, Ibaraki, Japan The stable MHD response of a high-beta JT-60U plasma was analyzed numerically for the first time. Onaxis toroidal beta values up to β = 3.5% were considered, which is a regime relevant for burning plasmas. The following results were obtained [1]: 1. Discrete MHD modes with dominant sound polarization are found in regions where the sound wave continua have a weak radial dependence. We call these modes global slow magnetosonic eigenmodes (GSME). 2. For β 1%, GSMEs overlap with continuous spectra of shear Alfvén waves and the two branches couple. This gives rise to new discrete modes with mixed Alfvén and sound polarization, which we call beta-induced Alfvén continuum modes (BACM). 3. When fast ions excite an energetic particle mode (EPM) [2] near the radius and frequency where such Alfvén -acoustic wave coupling occurs, the EPM wave packet is found to acquire features of a BACM. The EPM simulations were carried out with the hybrid MHD-gyrokinetic code MEGA, which was recently successfully validated against DIII-D and JT-60U experiments [3,4,5]. The EPMs in the JT-60U scenario studied here were driven by tangentially injected negative-ion-based neutral beam (N-NB) ions with a birth energy of about 400 kev. The above discoveries have several important implications. First, they reveal a new noncollisional self-heating channel for burning plasmas: Resonant Drive BACM Dissipative Heating Fast ions Alfvén waves Sound waves Thermal bulk ions. This finding motivates an intensification of research activity in the field of alpha particle energy channeling [6,7] with the goal to quantify how much the new Alfvén acoustic channel enhances fusion performance above previous estimates that were based on collisions with electrons only. Second, the above wave energy channeling and associated wave damping has implications for fast ion confinement. On the one hand, strong wave damping (strong self-heating, weak transport) is desirable at frequencies where newly born alpha particles (3.5 MeV) resonate. On the other hand, strong transport is desirable at mode frequencies where partially slowed down alpha particle ash (~100 kev) resonates. [1] Bierwage et al., Phys. Rev. Lett. 114 (2015) [2] Chen, Phys. Plasmas 1 (1994) [3] Todo et al., Nucl. Fusion 54 (2014) [4] Todo et al., Proc. 25th IAEA FEC 2014 (St. Petersburg, Russia), IAEA, Vienna (2015), invited TH/7-1. [5] Bierwage et al., Proc. 25th IAEA FEC 2014 (St. Petersburg, Russia), IAEA, Vienna (2015), poster TH/P7-39. [6] Fish and Rax, Phys. Rev. Lett. 69 (1992) 612. [7] Fish, Trans. Fusion Sci. Tech. 51 (2007) 1. 18

19 I-11: predictive nonlinear studies of tae-induced alpha-particle transport in the q=10 iter baseline scenario M. Fitzgerald 1, S. E. Sharapov 1, P. Rodrigues 2, S. Pinches 3, D. Borba 2 1 CCFE, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB, United Kingdom 2 Instituto de Plasmas e Fusão Nuclear, IST, Univ. de Lisboa, Lisboa, Portugal 3 ITER Organization, St Paul-lez-Durance Cedex, France Address of Submitting Author: Michael.Fitzgerald@ccfe.ac.uk We use the HAGIS code [1] to compute the nonlinear stability of the Q=10 ITER baseline scenario [2] to TAEs and the effects of these modes on fusion -particle redistribution. Our calculations build upon an earlier linear stability survey [3] carried out using the MISHKA and CASTOR-K codes, which identifies relevant TAEs and provides accurate values of bulk ion, impurity ion and electron thermal landau damping for our HAGIS calculations, as well as a benchmark for our linear -particle drive calculations. We also include analytical estimates for radiative damping. In linear calculations, it is found that even in the presence of / ~ 1% thermal bulk damping of core localised modes, -particle drive of core localised TAEs with toroidal mode numbers around n=29 can be as large as 3-5%, and thus linearly unstable with large growth rates. Nonlinear calculations of 88 TAEs in the range n=15-35 and subsequent effects on alpha particles have been performed. The effects of frequency sweeping were also included to examine possible phase space hole and clump convective transport. We find that core localised modes are dominant (expected from linear theory), and that linearly stable modes are destabilized nonlinearly. When damping is neglected, the core localised modes reach a maximum amplitude of B r / B , with global modes being smaller by an order of magnitude or more. 4 When damping is introduced, the maximum amplitude drops to / B 3 10 (Fig. 1). Stochastic transport occurs in a narrow region where the most unstable core localised modes are found (Fig 2), implying the formation of a transport barrier at r / a 0. 5, where the weakly driven global modes are found. We thus expect that for TAEs with n=15-35 in this scenario, -particle redistribution will be confined to a small region and losses will be negligible. We are currently extending the study to include TAEs with n=10-14, and will include modelling of these modes in the results presented at the conference. B r Figure 1. Amplitude growth and saturation of 88 TAEs including the effects of damping and unlocked mode phases. Figure 2. Poincare plots of test particle orbits in the presence of core localized (red) and global (blue) TAEs. This work has received funding from Euratom and the RCUK Energy Programme [grant number EP/I501045]. The views and opinions expressed herein do not necessarily reflect those of the European Commission.[1] Pinches, S. D. et al. (1998). Comput. Phys. Commun., 111, 133; [2] Polevoi, A. et al. (2002). J. Plasma Fusion Research, SERIES, 5, 82; [3] P.Rodrigues et al. (2015) submitted to Nuclear Fusion 19

20 I-12: progress in non-linear electromagnetic gyrokinetic simulations of toroidal alfvén eigenmodes M. D. J. Cole 1, A. Mishchenko 1, M. Borchardt 1, R. Hatzky 2, R. Kleiber 1, A. Könies 1 1 Max Planck Institute for Plasma Physics, Greifswald, Germany 2 Max Planck Institute for Plasma Physics, Garching, Germany Address of Submitting Author: mcole@ipp.mpg.de Gyrokinetic numerical simulation has been a successful tool for predicting the behaviour of magnetised plasmas in fusion devices. Global modes, such as the Toroidal Alfvén Eigenmode (TAE), at finite β require a global electromagnetic treatment. This is computationally demanding and can introduce conceptual numerical complications. Since such modes pose a threat to the operation of a viable fusion reactor, it is important to be able to predict and control their behaviour prior to the construction of such a device. In this work, we present the results of non-linear investigations of fast-ion driven TAEs using reduced models, which mitigate some of the numerical requirements. Furthermore, we describe the progress of on-going work using a model in which all species are treated gyrokinetically. 20

21 list of regular orals: O-1 M. Podesta Effects of fast ion phase space modifications by instabilities on fast ion modelling O-2 C. Hopf Recent progress in neutral beam current drive experiments on ASDEX Upgrade O-3 R. Waltz Development and validation of a critical gradient energetic particle driven Alfven eigenmode transport model for DIII- D tilted neutral beam experiments O-4 C. Collins Measurements of Alfven eigenmode induced fast-ion transport in DIII-D O-5 J. Rasmussen Investigating fast-ion transport due to sawtooth crashes using Collective Thomson Scattering O-6 N. Gorelenkov Validating predictive models for fast ion profile relaxation in burning plasmas O-7 N. Bolte Measurement and Simulation of Deuterium Balmer-Alpha Emission from First-Orbit Fast Ions and the Application to General Fast-Ion Loss Detection in the DIII-D Tokamak O-8 M. Schneller Nonlinear Energetic Particle Transport in the Presence of Multiple Alfvénic Waves in ITER O-9 J. Kim Experimental Observations of Fast-ion Losses on KSTAR O-10 M. Hole The impact of anisotropy and flow on magnetic configuration, and stability O-11 P. Rodrigues Sensitivity of alpha-particle driven Alfven eigenmodes to q- profile variation in ITER scenarios 21

22 O-12 F. Nabais Observation of chirping modes in JET at frequencies above the Alfven frequency O-13 L. Horváth Experimental investigation of the radial structure of energetic particle driven modes O-14 W. Zhang Verification and Validation of Gyrokinetic Particle Simulation of Fast Electron Driven beta-induced Alfven Eigenmode on HL-2A Tokamak O-15 S. Tripathi Excitation of waves by a spiraling ion beam in a large magnetized plasma O-16 D. Spong Analysis of energetic particle driven Alfven instabilities in 3D toroidal systems using a global gyrokinetic O-17 M. Garcia- Munoz Impact of localized ECRH on NBI and ICRH driven Alfven eigenmodes in the ASDEX Upgrade tokamak O-18 A. Melnikov The study of NBI-driven chirping mode properties and radial location by Heavy Ion Beam Probe in the TJII stellarator O-19 Y. Todo Simulation study of profile stiffness of fast ions interacting with multiple Alfven eigenmodes O-20 M. Van Zeeland Impact of Localized Electron Cyclotron Heating on Alfven Eigenmodes in DIII-D O-21 G. Papp Coupled kinetic-fluid simulation of runaway electron dynamics O-22 Z. Chen Study of disruption generated runaway electrons on J-TEXT tokamak 22

23 O-1 effects of fast ion phase space modifications by instabilities on fast ion modeling M. Podestà, M. Gorelenkova, N. N. Gorelenkov, E. Fredrickson and R. B. White Princeton Plasma Physics Laboratory, Princeton NJ , USA Address of submitting Author: mpodesta@pppl.gov Reduced models for energetic particle (EP) transport are emerging as an effective tool for long time-scale integrated simulations of tokamak plasmas, possibly including the effects of instabilities on EP dynamics. Available models differ in how EP distribution properties are modified by instabilities, e.g. in terms of gradients in real or phase space. It is therefore crucial to assess to what extent different assumptions in the models affect predicted quantities such as EP profile, energy distribution, Neutral Beam (NB) driven current and energy/momentum transfer to the thermal populations. A newly developed kick model, which includes modifications of the EP distribution by instabilities in both real and velocity space, is used to address these issues. The model condenses information on EP distribution response to instabilities, e.g. modeled through the particle following code ORBIT, in a EP transport probability. The latter can be included in the NUBEAM module of the TRANSP tokamak transport code, which computes EP evolution. Coupled to TRANSP simulations, the kick model is used to study NBheated NSTX discharges featuring unstable toroidal Alfvén eigenmodes (TAEs). Results show that TAEs selectively affect the EP energy distribution, with a decrement of 10-30% for the core NB driven current. When TAEs evolve in so-called TAE avalanches, the model reproduces the measured drops of ~10% in the neutron rate. Results from the kick model will be compared to those from a simple diffusive model and a critical gradient model, which postulate radial EP gradient as the only transport drive. The importance of EP modifications in real and velocity space is discussed in terms of accuracy of simulations vs. experimental results, with emphasis on Neutral Beam current. (Work supported by U.S. DOE Contract DE-AC02-09CH11466). 23

24 O-2: recent progress in neutral beam current drive experiments on asdex upgrade C. Hopf, D. Rittich, B. Geiger, A. Mlynek, M. Reich, A. Bock, A. Burckhart, C. Rapson, F. Ryter, the ASDEX Upgrade Team and the EUROfusion MST1 Team* Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, Garching, Germany * Past studies comparing neutral beam current drive with on- and off-axis beams at 5 MW gave contradicting results. In the first experiments anomalous fast-ion transport was needed to understand the current profiles constrained by MSE [1], but later similar experiments showed that the fast-ion density profile constrained by fast-ion D (FIDA) spectroscopy could be modelled by neoclassical theory alone [2]. It remained an open question whether this apparent contradiction pointed to a problem in NBCD theory, or whether it could be attributed to differences between the two sets of experiments. In 2014 a new effort was started to clarify this question. A modified heating scheme that uses a total of 7.5 MW NBI (three beams) while switching 5 MW between on- and off-axis beams allows for continuous FIDA and MSE measurements [2]. ECCD is employed to avoid MHD instabilities and feedback-controlled central ECRH keeps the T e profiles very constant between the on- and off-axis phases. The predicted higher current drive efficiency of the tangential off-axis beams is confirmed by the expected drop in the loop voltage. The on- and off-axis FIDA profiles qualitatively show the expected differences, but quantitative simulation of the off-axis profiles requires the assumption of anomalous fast ion diffusion localized at approximately half minor radius. MSE and the new Faraday rotation polarimetry ( FRP ) diagnostic, that is also sensitive to changes of the q profile, reveal changes in the driven current profile after switching from on- to off-axis NBI that are also in better agreement with the assumption of some anomalous fast ion transport. In the coming months our work will primarily focus on characterizing the conditions under which fast beam-ion transport is or is not neo-classical as well as improved quantification of the overall driven current in order to test NBCD theory. The experiments will also profit from the upgrades and improvements of the existing MSE and FRP systems as well as a new imaging MSE system. The present status of the ongoing studies will be reported. [1] S. Günter et al., Nucl. Fusion 47 (2007) [2] B. Geiger et al., Plasma Phys. Control. Fusion 57 (2015)

25 O-3: development and validation of a critical gradient energetic particle driven Alfven eigenmode transport model for diii-d tilted neutral beam experiments R. E. Waltz 1, E.M. Bass 2, W.W. Heidbrink 3, and M.A. VanZeeland 1 1 General Atomics, San Diego, CA 2 University of California San Diego, San Diego, CA 3 University of California Irvine, Irvine, CA Recent experiments with the DIII-D tilted neutral beam injection (NBI), which significantly vary the beam energetic particle (EP) source profiles, have provided strong evidence that unstable Alfven eigenmodes (AE) drive stiff EP transport at a critical EP density gradient[1]. We hope to identify the critical gradient with the condition that the maximum local AE growth rate falls to the local ITG/TEM rate at the same low-n toroidal mode number. This condition was supported by early nonlinear local GYRO simulations [2]. It is somewhat more optimistic than stiff EP transport at the AE marginal stability gradient used in a recent ITER projection of AE driven alpha confinement losses[3]. The AE and ITG/TEM growth rates are taken from GYRO with comparison of Maxwellian to slowing down beam-like EP distribution with slightly lower critical gardient. The critical gradient condition is to be verified by nonlinear GYRO simulations of the DIII-D NBI discharges with unstable low-n AE modes embedded in high-n ITG/TEM turbulence. The ALPHA EP density transport code[3] combines the lown stiff EP critical density gradient AE transport at the mid core radii with the Angioni et al [4] energy independent high-n ITG/TEM density transport model which controls the central core EP density profile. For the on-axis NBI heated DIII-D shot , while the net loss to the edge is small, about half the birth fast ions are lost from the central core r/a < 0.5 and the central density is about half the slowing down density. Results are in good agreement with the MHD equilibrium fit NBI fast ion pressure profile. [1] Heidbrink W.W., Van Zeeland M.A., et. al Nucl. Fusion 53, [2] Bass E.M. and Waltz R.E Phys. Plasmas 17, [3] Waltz R.E. and Bass E.M Nucl. Fusion 54, [4] Angioni C. and. Peters A. G Plasma Phys Acknowledgement: This work was supported by the U.S. Department of Energy under GA-Grant Nos. DE-FG02-95ER54309, DE-FC02-08ER54977, and DE-FC02-04ER

26 O-4: measurements of alfvén eigenmode induced fast-ion transport in diii-d C.S. Collins 1, W.W. Heidbrink 1, L. Stagner 1, C.C. Petty 2, D.C. Pace 2, M.A. Van Zeeland 2,Y.B. Zhu 1 1 University of California at Irvine, Irvine, CA 92697, USA 2 General Atomics, PO Box 85608, San Diego, CA , USA Address of submitting Author: collinscs@fusion.gat.com The onset threshold for fast-ion transport due to Alfvén eigenmode (AE) activity in DIII-D appears to differ between various fast-ion diagnostics, indicating a phase-space dependence of fast-ion transport. A method for measuring fast-ion transport using a source modulation technique will be discussed. In the experiment, the AE activity is varied with total neutral beam injected power, while the fast-ion pressure profile is modulated using an off-axis neutral beam. The neutral-particle analyzer (SSNPA) is sensitive to the trapped particle population and indicates sudden onset of transport at 6 MW beam power, while the neutron diagnostic, which is sensitive to the high-energy, counter-passing particles, exhibits threshold near 4 MW. Fast-ion Dα (FIDA) spectroscopy indicates radially localized transport of the co-passing population corresponding to the location of mid-core AEs. Transport is determined from the continuity equation for fast-ions, where the time evolution of the measured fast-ion population depends on the source (the modulated beam), the sink (fast-ion thermalization), and transport (due to resonant waveparticle interactions with AEs). The analysis is more complicated than conventional transport analysis techniques, since the measurement is a convolution of the fast-ion distribution function and the instrument weight function which depends on fast-ion energy, pitch, and the diagnostic geometry. The source can be calculated using TRANSP to find the classical fast-ion distribution function in the absence of transport, and the FIDASIM code produces synthetic FIDA and SSNPA signals. At the lowest beam power where transport is small, the modulated FIDA, SSNPA, and neutron signals closely match the simulated signals. At large beam powers, the measured signals deviate substantially from the classical simulations. Recent upgrades to the FIDA diagnostic enables comparison to an expanded phase-space, with 11 oblique viewing chords spanning the full radius and 3 vertical viewing chords. Pinpointing the onset of transport in phase-space and the scaling law for stiff transport beyond threshold is useful in validating critical gradient models [1,2] that aim to predict alpha profiles, beam ion profiles, and losses in future burning plasma devices. Work supported by the US Department of Energy under SC-G903402, DE-FC02-04ER54698 & DE-AC02-09CH References [1] Heidbrink W.W. et al, Nucl. Fusion 53, (2013). [2] Waltz, R.E. and Bass, E.M., Nucl. Fusion 54, (2014). 26

27 O-5: investigating fast-ion transport due to sawtooth crashes using collective thomson scattering J. Rasmussen 1, S. K. Nielsen 1, M. Stejner 1, A. S. Jacobsen 1, S. B. Korsholm 1, F. Leipold 1, M. Salewski 1, B. Geiger 2, F. Ryter 2, M. Schubert 2, J. Stober 2, D. Wagner 2, the ASDEX Upgrade Team 2, the EUROFusion MST1 Team 3 1 Technical University of Denmark, Department of Physics, DK-2800 Kgs. Lyngby, Denmark. 2 Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D Garching, Germany 3 Address of Submitting Author: jeras@fysik.dtu.dk Sawtooth crashes redistribute heat, particles, momentum, and large populations of fast ions radially outwards. As this can modify heating and current-drive profiles and potentially increase fast-ion losses, the impact of sawteeth on confined fast ions is a subject of particular interest for future fusion devices. A key challenge is to understand how the redistribution depends on fast-ion energy and pitch as well as on plasma parameters and the sawtooth crash amplitude or period. Collective Thomson Scattering (CTS) is well suited for studies of the mechanisms underlying fast-ion redistribution by sawteeth, given its flexible measurement geometry which allows measurements in specific regions of fast-ion phase space. Recently, at ASDEX Upgrade, the installation of a dedicated CTS receiver for background monitoring has helped to significantly improve the acquisition and analysis of CTS data, with CTS measurements of thermal and energetic ions in MHD-quiescent discharges showing good agreement with results from other diagnostics and with neo-classical theory. Building on this, we present the first CTS measurements of sawtooth-induced redistribution of fast ions at ASDEX Upgrade and compare the results with those predicted with the Kadomtsev sawtooth model implemented in TRANSP. We also discuss the results in light of those obtained using other fast-ion diagnostics such as fast-ion D-alpha spectroscopy (FIDA), neutral particle analysers (NPA) and fast-ion loss detectors (FILD) and consider what can be gained from a combined analysis of these measurements using tomographic reconstruction. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect those of the European Commission. 27

28 O-6: validating predictive models for fast ion profile relaxation in burning plasmas N. N. Gorelenkov 1, W.W.Heidbrink 2, G. J. Kramer 1, J. Lestz 1, M. Podesta 1, M.A. Van Zeeland 3, R. B. White 1 1 Princeton Plasma Physics Laboratory, Princeton University 2 University of California, Irvin 3 General Atomics, San Diego, California The redistribution and potential loss of energetic particles due to MHD modes can limit the performance of fusion plasmas by reducing the plasma heating rate. In this work, we present validation studies of a 1.5D or Critical Gradient Model (CGM) for Alfven eigenmode induced EP transport in NSTX and DIII-D beam heated plasmas. In previous comparisons with a single DIII-D L-mode case, the CGM model was found to be in surprisingly good agreement with measured AE induced neutron deficits [1]. Application to DIII-D advanced tokamak plasmas however, showed the need to expand the linear stability analysis to nonperturbative regimes [2]. With the use of the fully kinetic nonperturbative code HINST it is found that AEs show strong instability drive, γ/ω~ 20 30%, violating NOVA-K perturbative assumptions. In the CGM, it is assumed that all fast ions are affected, even when they are not in resonance with the underlying eigenmodes. This situation is natural for a plasma with strong collisions or strong AE overlapping. As shown in Fig. 1 (left) both models agree with each other and both underestimate the neutron deficit measured in the DIII-D shot. On the other hand in NSTX the application of CGM shows agreement with the measured flux deficit as shown in Fig. 1 (right). We discuss possible explanations of these DIII-D discrepancies between the measurements and CGM predictions. We also attempt to understand these results with the help of the guiding center code ORBIT. The ORBIT comparison allows insight into the underlying velocity space dependence of the AE induced EP transport. Figure 1. Neutron flux deficit computed with the help of CGM is compared with the measured deficit in DIIID shot # as shown in left figure. Shown on the right is the perturbative CGM application for NSTX plasma. [1] W.W. Heidbrink, M. A. Van Zeeland, M. E. Austin, E. M. Bass, K. Ghantous, N. N. Gorelenkov, B. A. Grierson, D. A. Spong, and B. J. Tobias, Nucl. Fusion 53, (2013). [2] N. N. Gorelenkov, W.W. Heidbrink, J. B. Lestz, M. Podesta, M. A. V. Zeeland, and R. B.White, Proc. 25nd IAEA Fusion Energy Conference, St. Petersburgh, Russia, CD-ROM file TH/P1-2, (2014). 28

29 O-7: measurement and simulation of deuterium balmer-alpha emission from first - orbit fast ions and the application to general fast - ion loss detection in the diii-d tokamak* Nathan G. Bolte 1, W.W. Heidbrink 1, D.C. Pace 2, M.A. Van Zeeland 2, Xi Chen 2 1 University of California, Irvine, CA, USA 2 General Atomics, San Diego, CA, USA Address of Submitting Author: NathanBolte@gmail.com A new fast-ion diagnostic method is developed that utilizes passive emission of Balmer-alpha radiation to determine fast-ion losses quantitatively. The purpose of this work is to put passive edge light measurements on a quantitative footing by comparing the measurement and simulation of spectra from beam prompt losses that charge exchange with the edge neutral population. Calibrated first-orbit spectra are used to estimate the neutral density 2D profile by inverting the simulated spectra to find the best neutral density in a least squares sense required to best match the experimental spectra. Successfully measuring and simulating first-orbit spectra then effectively calibrates the system, allowing for the quantification of more general fast-ion losses. Viewing geometry and the high energy of the fast ions produce Doppler shifts that effectively separate the fast-ion contributions from the bright, cold edge light while modulation of the fast-ion source allows for time-evolving background subtraction. The passive fast-ion Dalpha simulation (P-FIDAsim) forward models the spectra of these first-orbit fast ions and consists of a beam model, an ion orbit-calculating code, a collisional-radiative model, and a synthetic spectrometer. Eighty-six experimental spectra are obtained (and simulated) using six different neutral beam fast-ion sources and 13 different viewing chords for various operational conditions. Simulated spectra have an overall Spearman rank correlation coefficient with the shape of experimental spectra of 58% with subsets of cases rising to a correlation of 80%. The inferred 2D neutral density shows the expected increase toward each x-point with the average neutral density at cm 3 at the magnetic axis, cm 3 in the core, cm 3 at the plasma boundary, and cm 3 near the wall. Sawtooth crashes are estimated to eject 1.2% of the fast-ion inventory globally, in good agreement with a 1.7% loss estimate made by the TRANSP code. As expected, sightlines that are sensitive to passing ions observe larger sawtooth losses than sightlines that are sensitive to trapped ions. * This work was supported by the US Department of Energy under DE-FC02-04ER

30 O-8: nonlinear energetic particle transport in the presence of multiple alfvénic waves in iter M. Schneller 1, Ph. Lauber 1, S. Briguglio 2, X. Wang 1 1 Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, Garching, Deutschland 2 ENEA C.R. Frascati, CP Frascati, Italy Address of Submitting Author: mirjam.schneller@ipp.mpg.de As future fusion devices will exhibit large fractions of highly energetic particles (EP), the interplay of fast ions with Alfvénic instabilities is an important topic in fusion research. Strong EP transport might reduce the heating and current drive efficiencies, while losses could even damage the first wall. The aim of the here presented work is to enhance the understanding of interaction mechanisms between EP and multiple Alfvén waves in a realistic ITER case. The focus lies on the 15 MA baseline scenario, where a sea of small-amplitude perturbations is expected to be marginally unstable [1]. Based on quasi-linear estimates [2], the EP transport would be rather low. The question of interest here is, whether the EP population will drive linearly stable or weakly unstable modes nonlinearly unstable. As a consequence, dominolike transport can occur. Such behavior has been found already in realistic ASDEX Upgrade double-mode simulations [3], which could explain experimentally found EP losses [4]. Basis of the simulations is a nonlinear hybrid model, the driftkinetic HAGIS code [5]. As crucial new elements of a realistic scenario, the perturbation structures, frequencies and damping rates are taken as obtained from the gyrokinetic eigenvalue solver LIGKA [6]. Further, a new non-local damping mechanism has been implemented via accounting for a parallel electric field E ll. Although the nonlinear wave-particle interaction is calculated self-consistently within the HAGIS- LIGKA model, at the present status, other nonlinearities such as the evolution of wave structure are not included yet. Before extending the model in this direction, the expected effect of the radial wave structure evolution is investigated: HAGIS-LIGKA results are compared to those of a different hybrid code, HMGC [7], which already contains wave structure evolution. For that comparison, a newly implemented phase space diagnostic, the so called Hamiltonian Mapping Technique [8] is used. It allows for a detailed study of wave-particle interaction processes, especially in the view of nonlinear saturation mechanisms. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect those of the European Commission. References [1] P. LAUBER. Plasma Physics and Controlled Fusion, 57 (5): (2015). [2] K. GHANTOUS ET AL. Phys. Plasmas, 19 (9): (2012). [3] M. SCHNELLER ET AL. Nucl. Fusion, 53 (12): (2013). [4] M. GARCÍA-MUÑOZ ET AL. Phys. Rev. Lett., 104: (2010). [5] S. PINCHES ET AL. Comput. Phys. Commun., 111 (13):133(1998). [6] PH. LAUBER ET AL. J. Comp. Phys., 226 (1):447 (2007). [7] S. BRIGUGLIO ET AL. Phys. Plasmas, 5 (9):3287 (1998). [8] S. BRIGUGLIO ET AL. Phys. Plasmas, 21 (11):112301(2014). 30

31 O-9: experimental observations of fast-ion losses on kstar J.-H. Kim 1,2, J.-Y. Kim 2, T.N. Rhee 1, M. Isobe 3, K. Ogawa 3, K. Shinohara 4, M. Garcia-Munoz 5, Y.M. Jeon 1, S.H. Kim 6, and S. W. Yoon 1 1 National Fusion Research Institute, Gwahak-ro, Yuseong-gu, Daejeon , Korea 2 Korea University of Science and Technology, Gajeong-ro, Yuseong-gu, Daejeon , Korea 3 National Institute for Fusion Science, Oroshi-cho, Toki , Japan 4 Japan Atomic Energy Agency, Naka, Ibaraki , Japan 5 University of Seville, Av de la Reina Mercedes, Seville, Spain 6 Korea Atomic Energy Research Institute, 111 Daedeok-Daero, Yuseong-gu, Daejeon , Korea address of submitting author: kimju@nfri.re.kr Confinement and transport of fast-ions in the fusion plasmas becomes crucial as the performance of the fusion device has been elevated along with increase of heating power. As known well, loss of the fastions (auxiliary heated ions, fusion products and so on) can degrade the fusion performance and damage the first-wall. On KSTAR, mechanism of beam-ion loss has been studied experimentally through the energetic particle diagnostics such as scintillator-based fast-ion loss detectors (FILD), compact neutral particle analyzer (NPA) and so on. Various factors, affecting fast-ion loss, such as ELMs, edge magnetic perturbations, tearing modes, energetic particle modes have been investigated. Most clear response on the fast-ion loss is the ELM-induced one, and it has been found that the edge magnetic perturbations having various field spectra could cause different non-axisymmetric loss patterns. To understand the fastion loss behaviour responding to the non-axisymmetric magnetic perturbations, full 3-D orbit simulations using LORBIT and F3D-OFMC have been devoted and the calculated change in the pitch-angle distribution based on the vacuum field is matched well with the FILD measurements in several cases. Not only vacuum field simulation but also plasma-response will be considered to explain the discrepancy between the simulations and the experimental results depending on plasma β. In addition to the fast-ion loss associated with the edge activities, interactions with core MHD activities such as tearing modes and energetic particle modes have been observed. On the contrary to the edge-activity cases, fast-ion loss correlated with core activities seems to be case-sensitive since the interplay of the fast-ion orbit exploring the core region with the rotating modes may have to be synchronized, leading to the resonant interaction and loss. Finally near-term KSTAR energetic particle research plan is discussed. 31

32 O-10: the impact of anisotropy and flow on magnetic configuration, and stability M.J. Hole, M. Fitzgerald, Z. Qu, B. Layden Plasma Theory and Modelling Group, Australian National University, ACT 0200, Australia Address of Submitting Author: Recently, equilibrium models and reconstruction codes have been generalised to include physics of anisotropy and toroidal flow[1]. These codes have been used to explore the impact on the magnetic configuration in regimes with large neutral beam heating, as well as determine the impact on particular discharges [2]. In parallel to these developments, a single adiabatic extensions of MHD stability models that capture anisotropy and flow has been developed [3], and together with CGL models, implemented into the ideal MHD stability code MISHKA-ATF[4]. In this work we highlight the differences in the CGL / single adiabatic model continuum, and report on the impact of anisotropy and flow on the equilibrium, frequency and mode structure of a range of energetic particle driven modes in MAST. We also update development of generalisation of the wave-particle interaction code HAGIS to simulate plasmas with anisotropy and flow. 1 isotropic n=1, =0 anisotropic n=1, =0 1 p /p = 1.7 at s=0.5 outboard f /f A 88kHz f /fa 75kHz s 0 s 0 1 s s Figure 1: n=1, =0 continuous mode spectrum for MAST 29221@190ms EFIT-TENSOR reconstructions, for isotropic and anisotropic cases. The lower plots show calculations of the mode structure using MISHKA-ATF, showing a broader mode structure in the anisotropic case. [1] M. Fitzgerald, L. C. Appel, M. J. Hole, Nucl. Fusion 53 (2013) [2] Z S Qu, M Fitzgerald and M J Hole, Plasma Phys. Control. Fusion 56 (2014) [3] M Fitzgerald, M J Hole and Z S Qu, Plasma Phys. Control. Fusion 57 (2015) [4] Z.S. Qu, M.J. Hole and M. Fitzgerald, Plasma Phys. Control. Fusion, submitted 32

33 O-11: sensitivity of alpha-particle driven alfvén eigenmodes to q-profile variation in iter scenarios P. Rodrigues 1, A. C. A. Figueiredo 1, L. Fazendeiro 1 J. Ferreira 1, R. Coelho 1, F. Nabais 1, D. Borba 1, N. F. Loureiro 1, A. Polevoi 2, S. D. Pinches 2, and S. E. Sharapov 3 1 Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal. 2 ITER Organization, Route de Vinon-sur-Verdon, St Paul-lez-Durance Cedex, France. 3 CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom Address of Submitting Author: par@ipfn.ist.utl.pt Plasma heating during the burning regime in tokamak reactors will rely upon the energy of fusion-born alpha-particles which must be kept confined to keep the plasma hot and prevent wall damage. However, such particles can drive Alfvén Eigenmodes (AEs) unstable and be thus transported away from the plasma core, which would hamper the burning process. The complex interplay between energetic suprathermal particles and AEs is still not fully understood and recent research concerning ITER [1, 2, 3] has been focusing on the 15 MA baseline scenario [4]. In this work, the ASPACK [3] suite of codes is used to find how the linear-stability properties of AEs change in response to small variations of the background profiles. Of particular interest are the net growth-rate, wave numbers, and frequency of the most linearly-unstable AEs. These properties are shown to be significantly affected by small changes of the safety-factor profile. The consequences of these results for stability predictions of alpha-particle driven AEs in burning plasmas are also discussed. References [1] S. D. Pinches et al., Phys. Plasmas 22, (2015). [2] Ph. Lauber, Plasma Phys. Control. Fusion 57, (2015). [3] P. Rodrigues et al. Systematic linear-stability assessment of Alfvén eigenmodes in the presence of fusion a-particles for ITER-like equilibria, accepted in Nucl. Fusion (2015). [4] A. R. Polevoi et al., J. Plasma Fusion Res. SERIES 5, 82 (2002). 33

34 O-12: observation of chirping modes in jet at frequencies above the alfvén frequency F. Nabais 1, D. Borba 1, R. Coelho 1, L. Fazendeiro 1 J. Ferreira 1, A. Figueiredo 1, L. Fitzgerald 2, L. Menezes 1, P. Rodrigues 1, S. Sharapov 2 and JET Contributors EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK 1 Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal. 2 CCFE, Culham Science Centre, Abingdon OX14 3DB, UK. Address of Submitting Author: fnabais@ipfn.ist.utl.pt Modes propagating in the range of frequencies comprised between the Alfvén frequency and the cyclotron frequency are not normally observed in currently operating tokamaks. Notable exceptions are spherical tokamaks, like NSTX and MAST, and the conventional tokamak DIII-D operating with low magnetic field, where modes in this range of frequencies have been observed when super-alfvénic beams are injected into the plasma [1, 2, 3]. Moreover, these modes might be destabilized in ITER [3] and they may be important for stochastic heating of thermal ions [4] as well as for diagnostic purposes. This paper reports on the observation of fast chirping modes with frequencies above the Alfvén frequency in JET experiments. Contrary to the cases mentioned above, the modes observed in JET were destabilized by ICRH instead of NBI energetic ions. These experiments used low-density deuterium plasmas and high ICRH power, allowing a large population of energetic ions in the MeV range to build up in the plasma [5]. The observed modes share many characteristics with those described in [1, 2, 3]. They exhibit a fast chirping behavior and propagate both in the counter and co-current direction, appearing normally in groups with different bands forming sometimes intricate patterns. The frequency correlates with the magnetic field, suggesting an Alfvénic nature. The behavior of these modes is correlated with other instabilities, in particular with tornado modes and monster sawtooth crashes, and they seem to have little or no influence on the loss of fast ions from the plasma. [1] E.D. Fredrickson et al. Phys. Rev. Lett. 87, (2001) [2] L.C. Appel et al. Plasma Phys. Control. Fusion 50, (2008) [3] W.W. Heidbrink et al. Nucl. Fusion 46, 324 (2006) [4] N.N. Gorelenkov et al. Nucl. Fusion 43, 228 (2003) [5] F. Nabais et al. Nucl. Fusion 50, (2010) Acknowledgments -IST activities received financial support from Fundação para a Ciência e Tecnologia through project UID/FIS/50010/2013. See the Appendix of F. Romanelli et al., Proceedings of the 25th IAEA Fusion Energy Conference 2014, Saint Petersburg, Russia 34

35 O-13: experimental investigation of the radial structure of energetic particle driven modes L. Horváth 1*, G. Papp 2,3, G. I. Pokol 1, Ph. Lauber 3, G. Por 1, A. Gude 3, V. Igochine 3 and the ASDEX Upgrade Team 3 1 Institute of Nuclear Techniques, BME, Budapest, Hungary 2 Max-Planck/Princeton Center for Plasma Physics 3 Max Planck Institute for Plasma Physics, Garching, Germany Address of Submitting Author: horvath.laszlo@reak.bme.hu The understanding of energetic particle driven modes in tokamaks plays a key role regarding future burning plasma experiments. Energetic particles (EPs) can excite various instabilities. Alfvén eigenmodes (AEs) are often excited by EPs and in addition to these MHD normal modes, there are also energetic particle modes (EPMs) characterized by strong dependence on the fast-ion distribution function. One of the main open questions concerning EP driven instabilities is the non-linear evolution of the mode structure, because these instabilities constitute such a system where kinetic and MHD non-linearities can both be important making it difficult to describe the phenomenon [1]. The aim of the present contribution is to investigate the properties of beta-induced AEs (BAEs) and EP driven geodesic acoustic modes (EGAMs) observed in the ramp-up phase of off-axis NBI heated ASDEX Upgrade (AUG) discharges [2]. The interest is mostly focused on the changes in the mode structure of BAEs/EGAMs during the non-linear chirping phase. The analysis was carried out primarily using soft X-ray diagnostics (SXR), because these modes were well visible on several SXR line-of-sights which made it possible to analyse their spatial structure. The rapidly changing mode frequency and the low signal-to-noise ratio are handled with an advanced continuous linear timefrequency transform based method [3]. Our investigation shows that in case of the observed down-chirping BAEs the changes in the radial eigenfunction are smaller than the uncertainty of our measurement. In case of rapidly upward chirping EGAMs the analysis consistently shows shrinkage of the mode structure. This could be explained by that the resonance in the velocity phase space moves towards more passing particles which have narrower orbit width. References [1] W. W. Heidbrink, Physics of Plasmas 15, (2008) [2] Ph. Lauber et al., Presented at the 13th IAEA TCM, Beijing, China (2013) [3] L. Horváth et al., 41st EPS Conference on Plasma Physics 38F, P2.008 (2014) This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect those of the European Commission. 35

36 O-14: verification and validation of gyrokinetic particle simulation of fast electron driven beta-induced alfvén eigenmode on hl-2a tokamak * Wenlu Zhang 1,2, Junyi Cheng 1, Wei Chen 3, Limin Yu 3, Xuantong Ding 3 1 Institute of Physics, Chinese Academic of Science, Beijing , China 2 University of Science and Technology of China, Hefei, Anhui , China 3 Southwestern Institute of Physics, Chengdu, Sichuan , China Address of Submitting Author: wzhang@iphy.ac.cn A verification and validation study is carried out for a sequence of fast-electron driven beta-induced Alfven eigenmode (e-bae) in HL-2A tokamak plasma. The fast electron driven beta Alfvén eigenmode (e-bae) in toroidal plasmas is investigated for the first time using global gyrokinetic particle simulations, where the fast electrons are described by the drift kinetic model. The phase space structure shows that only the processional resonance is responsible for the e-bae excitations while fast-ion driven BAE can be excited through all the channels such as transit, drift-bounce, and processional resonance. Radial symmetry breaking around the rational surface is observed as expected due to the nonperturbative effects in the kinetic simulations, and the poloidal mode structure shows a different rotation direction for e-bae and i-bae simulations, this is due to the different direction of toroidal procession in the e-bae and i-bae excitations. * Supported by National Special Research Program of China For ITER 36

37 O-15: excitation of waves by a spiraling ion beam in a large magnetized plasma S. Tripathi 1, B. V. Compernolle 1, W. Gekelman 1, P. Pribyl 1, W. Heidbrink 2 1 Physics and Astronomy, University of California at Los Angeles, Los Angeles, CA 90095,USA 2 Physics and Astronomy, University of California at Irvine, Irvine, CA 92697, USA Address of Submitting Author: tripathi@physica.ucla.edu An ion source (25 kev, 10 A, 0.3 Hz rep rate, ms pulse-width) has been constructed for performing fusion-relevant fast-ion studies on the Large Plasma Device (LAPD), which produces a cylindrical magnetoplasma (19 m long, 0.6 m diameter) with ms pulse width and 1-Hz repetition rate. The ion source [1] was used to inject a spiraling hydrogen ion beam into the ambient plasma with single and two ion species (n cm -3, T e = ev, B = T, He + and H + ions). The interaction of the beam with the plasma was diagnosed using retarding-field energy analyzers, threeaxis magnetic-loops, and Langmuir probes. Measurements of the beam profiles at multiple axial locations evinced a spiraling ion-beam (J ma/cm 2, pitch-angle 53 ) that traveled at Alfvénic speed (beam-speed/alfvén-speed = ). A multitude of waves were spontaneously excited by the beam in the drift, shear Alfvén, ion cyclotron, and lower hybrid frequency ranges. This presentation gives an overview of the experiment and provides details of the resonant excitation of shear Alfvén waves through Doppler-shifted ion-cyclotron resonances (DICR) with the ion beam [2]. Parameters of the beam and ambient plasma were varied to examine the resonance conditions under a variety of scenarios. The experimental results demonstrate that the DICR process is particularly effective in exciting left-handed polarized shear Alfvén waves that propagate in the direction opposite to the ion beam. References: [1] Tripathi et. al., Rev. Sci. Instrum. 82, (2011) [2] Tripathi et. al., Phys. Rev. E 91, (2015) Work jointly supported by U. S. Department of Energy (Grant No. DOE-DE-FC02-07ER-54918) and National Science Foundation, USA (Grant No. NSF-PHY ) and performed at the Basic Plasma Science Facility, UCLA. 37

38 O-16: analysis of energetic particle driven Alfvén instabilities in 3D toroidal systems using a global gyrokinetic model D. A. Spong 1, I. Holod 2 1 Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN , U. S. A. 2 University of California - Irvine, Department of Physics and Astronomy, Irvine, CA U. S. A. Recently there has been increasing interest in the physics of toroidal devices with 3D field modifications. Energetic particle physics can play an important role in these devices for many of the same reasons as in axisymmetric tokamaks (protection of PFCs, loss of heating efficiency and diagnostic uses). 3D configurations modify EP physics through: emergence of new gap structures, larger finite orbit width effects, and the need to consider mode families with multiple toroidal mode numbers. To address these issues, the GTC global gyrokinetic PIC model has been adapted to 3D VMEC equilibria and provides a new method for the unified analysis of Alfvénic instabilities in stellarators, 3D tokamaks, and helical RFP states. The gyrokinetic orderings (k /k << 1, ω/ωci << 1, ρ EP /L << 1) are applicable to a wide range of energetic particle driven instabilities that have been observed in 3D configurations. This talk will describe the GTC global gyrokinetic model, its adaptation to 3D systems, and recent results. Applications of this model to stellarators have indicated that a variety of different Alfvén instabilities can be excited, depending on the toroidal mode number, fast ion average energy and fast ion density profile. TAE, EAE and GAE modes have been found in the simulations, depending on the mode family and fast ion profiles used. The dynamical evolution of the instabilities shows the field period coupling between n and n + N fp, as expected for 3D configurations. Applications to other devices and the development of gyrofluid models that can capture relevant physics aspects of the gyrokinetic models will also be discussed. Figure 1 3D and 2D (fixed toroidal plane)mode structure of an n 3 TAE instability in the LHD stellarator. Acknowledgment: Work supported by U.S. Department of Energy, Office of Science Contract No. DE-- AC OR and under the U.S. DOE SciDAC GSEP Center. 38

39 O-17: impact of localized ecrh on nbi and icrh driven alfvén eigenmodes in the asdex upgrade tokamak M. Garcia-Munoz 1,2, M. A. Van Zeeland 3, S. Sharapov 4, I. G. J. Classen 5, B. Bobkov 2, J. Galdon-Quiroga 1, B. Geiger 2, V. Igochine 2, P. Lauber 2, N. Lazanyi 6, F. Nabais 7, D. C. Pace 3, M. Rodriguez-Ramos 1, L. Sanchis-Sanchez 1, M. Schneller 2, A. Snicker 8, J. Stober 2 and the ASDEX Upgrade Team 1 FAMN Department, Faculty of Physics, University of Seville, Seville, Spain 2 Max Planck Institut fur Plasmaphysik, Garching, Germany 3 General Atomics, PO Box 85608, San Diego, CA , USA 4 Culham Center for Fusion Energy, Culham Science Center, Abingdon, Oxfordshire, UK 5 FOM-Institute DIFFER, Nieuwegein, The Netherlands 6 BME NTI, Budapest, Hungary 7 Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Portugal 8 Aalto University, Espoo, Finland NBI driven Alfvén Eigenmodes (AEs) are routinely obtained in the ASDEX Upgrade (AUG) toakamak during the current ramp-up phase with early NBI heating and reversed q-profile. Most commonly observed AEs comprise Reversed Shear Alfven Eigenmodes (RSAEs) and Toroidal Alfven Eigenmodes (TAEs). Recent experiments have been carried out in AUG to affect the observed AE activity via localized ECRH. ECRH is applied a few ms after the onset of the AE activity at different radial positions to study the impact that localized ECRH has on the observed AE activity. For ECRH injection near q min, (RSAEs location) the overall mode activity is significantly reduced. While in DIII-D, the unstable modes shift from strong RSAEs to weaker global TAEs and reminiscent RSAEs are visible only at their highest frequencies during their transition to TAEs [1], in AUG, almost all mode activity disappears with ECRH injection near q min. With reduced or no mode activity, the fast-ion confinement is significantly improved, in fact, the fast-ion profile measured with Fast-Ion D-Alpha (FIDA) spectroscopy matches classical TRANSP predictions. In agreement with this observation, and with classical fast-ion profiles, no fast-ion losses induced by AEs are observed by the Fast-Ion Loss Detectors (FILD) systems. Similar experiments with ICRH driven AEs do not exhibit the same reduction in RSAE activity with ECRH near q min. Future sensitivity experiments and modelling will focus on understanding this difference and the overall impact that the slightly ECRH modified q-profile, T e and fast-ion pressure may have on the observed AE activity. Stability and transport analysis have been started using MISHKA/CASTOR-K, LIGKA/HAGIS and ASCOT codes and will be discussed. [1] M.A. Van Zeeland, et. al., Plasma Phys. Control. Fusion (2008) 39

40 O-18: the study of nbi-driven chirping mode properties and radial location by heavy ion beam probe in the tj-ii stellarator A.V. Melnikov 1, 2, E. Ascasibar 3, A. Cappa 3, L.G. Eliseev 1, C. Hidalgo 3, A.S. Kozachek 4, L.I. Krupnik 4, M. Liniers 3, S.E.Lysenko 1, J.L. depablos 3, S.V. Perfilov 1, V.N. Zenin 1, HIBP group 1, 3, 4 and TJ-II team 2 1 National Research Centre Kurchatov Institute, , Moscow, Russia 2 National Research Nuclear University MEPhI, Moscow, Russia 3 Fusion National Laboratory, CIEMAT, 28040, Madrid, Spain 4 Institute of Plasma Physics, NSC KIPT, , Kharkov, Ukraine Alfven Eigenmodes were studied in low magnetic shear flexible heliac TJ-II (B 0 =0.95 T, <R>=1.5 m, <a>=0.22 m) NBI heated plasmas (P NBI 1.1 MW, E NBI =32 kev) by Heavy Ion Beam Probe (HIBP) [1, 2, 3]. The L-mode hydrogen plasma was investigated at various magnetic configurations with rotational transform a /2 q ~ Co-, counter and balanced beam injection were explored. HIBP is capable to measure simultaneously the oscillations of the plasma electric potential, density and poloidal magnetic field. Earlier studies have shown the chirping modes with 250 khz< f AE <380 khz at the combined ECR and NBI heated plasmas with low density n e = ( ) m -3 [3, 4]. Here we report the observation of the chirping modes with the similar properties with NBI heating only (no ECRH) at the similar densities, obtained due to Lithium treatment of the vacuum vessel [5]. Thus one may suggest that the ECRH is not necessary ingredient to obtain chirping modes in TJ-II by itself, rather an instrument, helping to get low density discharges. HIBP shows the location of the specific AE chirping mode at 0.4 < < 0.8. Dual HIBP [6], consisting of the two HIBPs, separated at ¼ of the torus shows the high coherence between the plasma potential and density oscillations during the period of the frequency burst. [1] R. Jiménez-Gómez et al Nuclear Fusion 51 (2011) [2] A.V. Melnikov et al Nuclear Fusion 50 (2010) [3] K. Nagaoka et al Nuclear Fusion 53 (2013) [4] A. Cappa et al 25-th IAEA FEC 2014, EX/P4-46. Nucl. Fusion, submitted. [5] F.L. Tabares et al Plasma Phys. Control. Fusion 50 (2008) [6] J.L. De Pablos et al SOFT 2014, P Fusion Engineering and Design, Submitted. 40

41 O-19: simulation study of profile stiffness of fast-ions interacting with multiple alfvén eigenmodes Y. Todo 1, 2, M. A. Van Zeeland 3, W. W. Heidbrink 4 1 National Institute for Fusion Science, Toki, Gifu , Japan 2 SOKENDAI (The Graduate University for Advanced Studies), Toki, Gifu , Japan 3 General Atomics, PO Box 85608, San Diego, CA 92186, USA 4 University of California, Irvine, CA 92697, USA Address of Submitting Author: todo@nifs.ac.jp A multi-phase simulation, which is a combination of classical simulation and hybrid simulation for energetic particles interacting with a magnetohydrodynamic (MHD) fluid including neutral beam injection (NBI), slowing-down, and pitch angle scattering, was applied to DIII-D discharge # [1,2]. The large fast ion pressure profile flattening and the electron temperature fluctuations brought about by multiple Alfvén eigenmodes (AEs) were successfully reproduced with the simulation. Recently, we performed an NBI power scan using the equilibrium data of DIII-D discharge # to investigate fast ion profile stiffness. The range of the power scan is from 1.56MW to 12.5MW with the experimental power 6.25MW. The simulation results of stored fast ion energy versus NBI power are shown in Fig. 1. We see in the figure the stored fast ion energy increases with the NBI power but reduced from the classical level. For the lowest power 1.56MW, multiple AEs are already destabilized, but the stored energy is close to the classical level because only the AEs located close to the plasma center are destabilized and the amplitudes are low. Saturation of stored fast ion energy expected for profile stiffness does not take place for the cases investigated. Detailed analyses of resonance overlap will be performed and the condition for the profile stiffness will be discussed. Figure 1. Stored fast ion energy versus NBI power for classical and multi-phase hybrid simulation [1] Y. Todo et al., Nucl. Fusion 54 (2014) [2] Y. Todo et al., to appear in Nucl. Fusion 55 (2015). 41

42 O-20: impact of localized electron cyclotron heating on alfvén eigenmodes in diii-d* M.A. Van Zeeland 1, A. Cappa 2, W. W. Heidbrink 3, S.E. Sharapov 4, E.M. Bass 5, C. Collins 3, M. Garcia-Munoz 6, G.J. Kramer 7, Z. Lin 3, D.C. Pace 1, C. Petty 1, D. Spong 8 1 General Atomics, PO Box 85608, San Diego, CA , USA Address of Submitting Author: vanzeeland@fusion.gat.com 2 Laboratorio Nacional de Fusión -CIEMAT Madrid, Spain 3 University of California at Irvine, Irvine, CA 92697, USA 4 CCFE, Culham Science Centre, Abingdon, Oxon, OX14 3DB, UK 5 University of California San Diego, 9500 Gilman Dr., La Jolla, CA , USA 6 Max-Planck-Institut für Plasmaphysik, Euratom Association, Garching, Germany. 7 Princeton Plasma Physics Laboratory, PO Box 451, Princeton, NJ , USA 8 Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA Localized electron cyclotron heating (ECH) can have a dramatic effect on neutral beam driven Alfvén eigenmode activity in DIII-D reversed magnetic shear plasmas. The most commonly observed effect is a shift in the dominant observed modes from a mix of reversed shear Alfvén eigenmodes (RSAEs) and toroidicity induced Alfvén eigenmodes (TAEs) to a spectrum of weaker TAEs when ECH is deposited near the shear reversal point (q min ) [1,2]. ECH deposition near the magnetic axis typically increases the unstable mode amplitudes and resultant fast ion transport. A recent experiment to understand the physical mechanisms responsible for this shift in AE stability utilized a simplified oval geometry and, in addition to ECH injection location, included variations of current ramp rate, ECH injection timing, beam injection geometry (on/off-axis), and neutral beam power. Essentially all variations carried out in this experiment were observed to change the impact of ECH on AE activity significantly. In some cases, RSAEs were observed to be more unstable with ECH near q min as opposed to near q0, in contrast to the original DIII-D experiments. It is found that for many of the intervals with minimal RSAE activity, or RSAEs with a much reduced frequency sweep range, that the geodesic acoustic mode (GAM) frequency at q min is very near or above the nominal TAE frequency - suggesting the so-called beta suppression mechanism [3] is important in these plasmas. A simple analytic model that incorporates this reduction in RSAE chirp range is in agreement with the observed spectra and appears to capture the relative balance of TAE or RSAE like modes. A database analysis of these discharges also shows a persistent trend for lower mode amplitude and a shift from TAE to RSAE dominated as the current penetrates and q min decreases. Detailed non-perturbative calculations of the observed shift in RSAE stability with ECH deposition are underway and will also be presented. *This work was supported by the US Department of Energy under DE-FC02-04ER-54698, DE-FG03-94ER54271, DE-FG02-08ER54984, DE-AC02-09CH11466, DE-SC ,DE-AC05-00OR [1] M.A. Van Zeeland, et.al PPCF 50 (2008) [2] M.A. Van Zeeland, et.al Nucl. Fusion 49 (2009) [3] Fredrickson et al Phys. Plasmas 14 (2007)

43 O-21: coupled kinetic-fluid simulation of runaway electron dynamics G. Papp 1, A. Stahl 2, Ph. W. Lauber 1 and T. Fülop 2 1 Max Planck Institute for Plasma Physics, Garching, Germany. 2 Department of Applied Physics, Chalmers University, Göteborg, Sweden Reliable runaway electron (RE) mitigation after disruptions is one of the most important challenges for safe ITER operation [1]. A proper understanding of the generation and losses of REs is therefore essential. A full MHD simulation of the disruption is a complex and computationally demanding task. Therefore, reduced dimension fluid-type" models are employed to describe the evolution of plasma parameters during disruptions with reasonable accuracy. One of these codes is GO [2], which uses a self-consistent, onedimensional model to calculate the evolution of electric field, plasma parameters and runaway current and is also capable of taking into account impurity injection using a collisional-radiative model based on ADAS data. GO has already been applied to various tokamaks to better understand the runaway evolution during mitigated or unmitigated disruptions [1, 2], and its physics model is being continuously extended. There are several applications however, that demand the knowledge of the electron distribution function. Accurate estimates of wall damage, calculation of the interaction with partially ionised high-z materials, calculation of synchrotron or bremsstrahlung emission (for diagnostic purposes), possibilities for particle-wave interactions, even constraining equilibrium reconstructions requires an energy- and pitch resolved distribution. We use the 2 dimensional Fokker-Planck solver CODE [3] to calculate the momentum-space distribution of runaway electrons for time-evolving plasma parameters. As the next step in self-consistent runaway modelling, we are coupling GO with CODE to obtain the 3 dimensional evolution of the f e (p ll ; p, r, t) electron distribution. In the future, coupling with more sophisticated solvers (e.g. the 3 dimensional LUKE [4]) is planned. In this paper we report on the recent progress and the complexities involved with implementing such self-consistent calculations. We also present the implications of the coupled model and its components in the view of recent experimental results [5]. References [1] E. M. Hollmann et al., PoP (2015) [2] G. Papp et al., Nuclear Fusion (2014) [3] A. Stahl et al., PRL (2015) [4] J. Decker et al., PSFC/RR-05-3 (2005) [5] G. Pautasso et al., EPS Conference (2015) This research was partially funded by the Max-Planck/Princeton Center for Plasma Physics. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect those of the European Commission. 43

44 O-22: study of disruption generated runaway electrons on j-text tokamak Z. Y. Chen, D. W. Huang, Y. H. Luo, Y. Tang and J-TEXT Team College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, , China Address of Submitting Author: Runaway currents following disruptions have an important effect on the first wall for the next generation tokamak. The behaviors of runaway currents in massive gas injection (MGI) induced disruptions have been investigated in the J-TEXT tokamak. It is found that MGI of He or Ne result in runaway free shutdown with different amount of gas injection. Moderate amount injection of Ar prone to produce significant runaway current. A fast frame camera diagnostics has been developed to study the penetration of impurities gas jet on J-TEXT. The cold front induced by the gas jet propagated into the plasma interior in the order of 200 m/s. The cold front was stopped at the location near the q=2 surface. The resonant magnetic perturbation (RMP) has been applied to reduce runaway production during disruptions. It is found that both the amplitude and the length of runaway current can be reduced by the application of RMP during the disruptions as shown in Fig.1. Fig.1. Runaway current induced by Ar MGI at 0.4s. With the application of RMP, both the amplitude and the length of runaway current are reduced. 44

45 list of posters: Poster Session I Wednesday 2nd September, P-1 M. Gryaznevich Towards Compact Fusion Reactor: Fast Particle Issues P-2 Y. Kolesnichenko Effects of large-scale perturbations on the transport of energetic ions in tokamaks P-3 K. Schoepf TAE induced alpha particle and energy transport in ITER P-4 D. Darrow Beam ion susceptibility to loss in NSTX-U plasmas P-5 V. Yavorskij Experimental investigation of ELM-induced fast-ion losses at the ASDEX upgrade tokamak P-6 R. Farengo The effect of perturbed electric fields and atomic processes on the redistribution of energetic particles P-7 S. Yamamoto Studies of fast ion losses caused by MHD instabilities by using Faraday cup type lost ion probe in Heliotron J plasmas P-8 M. Homma Simulation Study of Triton Confinement and Nuclear Reaction in the Deuterium Plasma Experiment at LHD P-9 H. Yamaguchi Evaluation of fluxes of lost alphas for gamma-ray diagnostics in ITER P-10 S. Murakami Development of nonlinear collision operator for the Monte Carlo simulation code in toroidal plasmas P-11 F. Jaulmes Numerical and experimental study of the redistribution of energetic and impurity ions by sawteeth in ASDEX Upgrade experiments 45

46 P-12 T. Kurki-Suonio Effect of the European design of TBMs on ITER wall loads due to fast ions in the baseline (15MA), hybrid (12.5MA), steady-state (9MA) and half-field (7.5MA) scenarios P-13 D. Liu Comparison of fast ion confinement during on-axis and off-axis neutral beam experiments on NSTX-U P-14 M. Nocente Numerical investigation of fast ion losses induced by resonant magnetic perturbation and edge localized modes at ASDEX Upgrade P-15 B. Layden Pressure anisotropy and flow suppress diamagnetic holes in high-beta tokamaks P-16 K. Shinohara Investigation of fast ion behavior using orbit following Monte-Carlo code in magnetic perturbed field in KSTAR P-17 N. Bolte Fast Particle Physics and its Connection to Performance on C-2 P-18 L. Xu Fishbone activity in EAST neutron beam injection plasma P-19 Z. Lin Progress in gyrokinetic particle simulation of Alfven instabilities P-20 N. Lazanyi Experimental investigation of ELM-induced fast-ion losses at the ASDEX Upgrade tokamak P-21 M. Mantsinen Analysis of ICRF heating and ICRF-driven fast ions in recent JET experiments P-22 J. Ferreira A stability study of α-particle driven Alfvén eigenmodes in JET D-T plasmas 46

47 I-1 P. Schneider Overview of diagnostic enhancements and physics studies of confined fast-ions in ASDEX Upgrade I-2 I. Furno Non-diffusive transport of suprathermal ions in toroidally magnetized plasmas I-3 W. Heidbrink Experimental determination of the threshold for stiff fast-ion transport by Alfven eigenmodes I-4 D. Pfefferle Alpha particle confinement in the European DEMO I-5 M. Schneider Modelling 3rd harmonic Ion Cyclotron acceleration of D beam for JET Fusion Product Studies experiments 47

48 P-1: towards compact fusion reactor: fast particle issues M Gryaznevich Tokamak Energy Ltd, Culham Science Centre, Abingdon, OX14 3DB, UK of Submitting Author: Mikhail.gryaznevich@tokamakenergy.co.uk Fusion reactor based on a compact high field Spherical Tokamak (ST) and specific issues connected with the fast particle and alpha particle physics are discussed in this talk. Encouraging results on a strong favourable dependence of electron transport on higher toroidal field (TF) in Spherical Tokamaks [1] open new prospects for a high field ST as a very compact fusion reactor. The combination of the high (ratio of the plasma pressure to magnetic pressure), which has been achieved in STs [2], and the high TF that can be produced by HTS TF magnets [3], opens a path to lower-volume burning plasma devices and fusion reactors. As a step towards such compact fusion reactor, a new tokamak, ST40, is being constructed at Culham, UK. The main goal of this compact device (R 0 ~ m, R/a ~ , B t /I pl = 3T/2MA, k~2.5, pulse duration ~ several seconds) is to achieve predicted high performance of an ST at high field, aiming at the burning plasma conditions. Update on the construction status of ST40 will be given. Neutral beam injection with two different energies, E b ~ 40keV and ~120keV, will be used in ST40 for heating and current drive (CD). New approach to optimization of the current drive in a compact ST reactor is based on a possibility to produce significant toroidal rotation in an ST using optimized neutral beam injection (e.g. with reduced E b ). However, CD and neutron production (where beam-plasma interaction will play a dominant role in D-D operations), require higher E b. These result in several challenges in the fast particle physics area due to large orbits and small cross-section of the ST40. Results of optimization of the NBI for direct CD and for the torque, using NUBEAM, NFREYA, FIFPC and ASCOT codes, will be presented to show that these conditions are quite different in the optimized beam energy and in the launch geometry due to difference in the beam deposition and in the fast ion losses. Due to relatively low for an ST toroidal beta (at high toroidal field), TAE modes may play significant role. Full-orbit simulations of alpha particles in a compact ST reactor show a possibility of a significant reduction of the necessary (for α containment) plasma current. This reduction is very important as it could reduce the auxiliary power required for CD in a solenoid-less ST reactor, which may significantly enhance the economics of the energy production. Although ST40 is not designed for tritium operations, trace of T experiments are under consideration. [1] VALOVIC, M., et al, (2009) Nucl Fus [2] GRYAZNEVICH, M., et al, Achievement of Record beta in START Spherical Tokamak (1998) Phys Rev Lett [3] GRYAZNEVICH, M., et al, Progress in applications of HTS in Tokamak Magnets (2013) Fus Eng & Des

49 P-2: effects of large-scale perturbations on the transport of energetic ions in tokamaks Ya.I. Kolesnichenko, O.S. Burdo, V.V. Lutsenko, B.S. Lepiavko, M.H. Tyshchenko, Yu.V. Yakovenko Institute for Nuclear Research, Prospekt Nauky 47, Kyiv 03680, Ukraine of Submitting Author: Large-scale perturbations perturbations with low mode numbers (m and n) often occur in toroidal plasmas. The purpose of this work is to consider the influence of these perturbations on the transport of the energetic ions. The results to be reported include those of Refs. [1,2] and can be summarized as follows. It is shown that the destabilization of Geodesic Acoustic modes (GAM and Energetic-particle-induced GAM, i.e., E-GAM) by passing energetic ions in tokamaks can be accompanied with a considerable energy transfer from these ions to the mode. This is the case when the mode is global and the plasma density perturbation is large, which provides wave-particle interaction in a wide phase-space region. It is found that the mode-induced slowing down of the energetic ions leads to a radial shift outwards / inwards of the ions moving in the direction counter- / co- to the plasma current, in spite of the fact that the canonical angular momentum of the particles is conserved during GAMs. Limits of applicability of these results and some consequences of the considered transport are discussed. The energetic-ion transport caused by radial displacements of particle resonances ( bucket transport ) due to the collisional slowing down of the ions and / or the temporal evolution of the magnetic configuration is considered. It is found that in these cases the problem can be reduced to analysis of the Hamiltonian introduced in [3] (where the transport caused by the frequency chirping was studied). It is concluded that regardless of the direction of the bucket motion, the total flux (involving both resonant and non-resonant particles) is always directed against the gradient of fast-ion density. The bucket transport may be of importance in the hybrid operation mode and in reversed-shear discharges. The analysis carried out deals with zero-frequency perturbations; in addition, the 0 case is discussed. The work is partly supported by the STCU-NASU project No and NASU the Project No. 0114U [1] Ya.I. Kolesnichenko, V.V. Lutsenko, B.S. Lepiavko, Phys. Lett. A 378 (2014) [2] Yu.V. Yakovenko, O.S. Burdo, Ya.I. Kolesnichenko, M.H. Tyshchenko, Phys. Lett. A, submitted. [3] C. T. Hsu, C. Z. Chang, P. Helander, D. J. Sigmar, R. White, Phys. Rev. Lett. 72 (1994)

50 P-3: tae induced alpha particle and energy transport in iter K. Schoepf, E. Reiter, T. Gassner Institute for Theoretical Physics, University of Innsbruck, Austria of Submitting Author: Mechanisms relevant to fast-ion transport in tokamaks are investigated and numerically modelled for a qualitative as well as quantitative evaluation of their effects. In this context the Fokker-Planck code FIDIT is used to describe the convective-diffusive transport, and the non-linear perturbative particle-incell code HAGIS is employed to simulate self-consistently the interaction of energetic particles and MHD waves. Properly switched upon checking stability/instability criteria, the iterative running sequence of these codes enables the study of combined transport effects, e.g. the convective-diffusive loss of energetic ions that are redistributed by waves. The iterative HAGIS/FIDIT coupling renders possible a longer-time simulation of the transport behavior of fast ions in plasmas with MHD mode activity. Referring to ITER scenario 2 (standard H-mode) with a constant DT fusion source we considered the presence of 15 TAE modes and evaluated synergetic transport effects caused by the coaction of wave-particle interplay and classical particle transport. As expected, a rapid loss of highenergetic fusion alphas became evident. When the fast ion pressure reached a high enough value for driving TAEs to significant amplitudes, a corresponding outward redistribution and loss of fusion born alphas was demonstrated. Following this redistribution a substantial transport of precedently relocated alphas was observed. Highly energetic alphas were shifted to the outer plasma edge in the wake of the wave-particle interaction, where stronger convective-diffusive transport further enhanced by the magnetic field ripples caused the loss of a significant portion of fast ions. Following the loss by redistribution through interaction with TAEs, an additional decrease in particle number and energy is observed, which results in a total loss of about 20% in particle number and energy content of fusion alphas. While the alpha energy content increases quickly again, the total alpha particle number is still decreasing until about 100 ms after the redistribution. Thus one can deduce that the alphas with highest energy are removed first from the plasma due to ripple-enhanced diffusion at the plasma edge. This transport happens slower for particles with lower energies. Since the fusion source is active all the time and new alphas with 3.5 MeV are continuously born, the alpha energy content increases earlier, as then only redistributed alphas with lower energies are removed from the plasma. 50

51 P-4: beam ion susceptibility to loss in nstx-u plasmas D. S. Darrow, E. D. Fredrickson, M. Podestà and R. White Princeton Plasma Physics Laboratory, Princeton, NJ 08543, USA D. Liu University of California, Irvine, Irvine, CA 92697, USA of Submitting Author: NSTX-U will operate with three additional neutral beam sources whose tangency radii of 1.1, 1.2, and 1.3 m are significantly larger than the 0.5, 0.6, and 0.7 m tangency radii of the neutral beams previously used in NSTX. These latter beams will also be retained for NSTX-U. Here, we attempt to formulate an estimate of the susceptibility of the beam ions from all the various sources to loss under a range of NSTX-U plasma conditions. This estimation is based upon TRANSP calculations of beam ion deposition in phase space, and the location of the FLR-corrected loss boundary in that phase space. Since TAEs were a prominent driver of beam ion loss in NSTX, we incorporate their effects through the following process: NOVA modeling of TAEs in the anticipated NSTX-U plasma conditions gives the mode numbers frequencies and mode structures that are likely to occur. Using this information as inputs to the guiding center ORBIT code, it is possible to find resonant surfaces in the same phase space along which beam ions would be able to diffuse under the influence of the modes. The degree to which these resonant surfaces intersect both the beam deposition volume and the orbit loss boundary should then give a sense of the susceptibility of that beam population to loss from the plasma. Work supported by U.S. DOE DE-AC0209CH11466, DE-FG02-06ER54867, and DE-FG03-02ER

52 P-5: fokker-planck model for collisional loss of fast-ions in tokamaks V. Yavorskij 1,2, V. Goloborod ko 1,2, K. Schoepf 1 1 Institute for Theoretical Physics, University of Innsbruck, Austria (fusion@oeaw) 2 Institute for Nuclear Research, Ukrainian Academy of Sciences, Kyiv, Ukraine of Submitting Author: Victor.Yavorskij@uibk.ac.at Modelling of the collisional loss of fast ions from tokamak plasmas is important from the point of view of the impact of fusion alphas and NBI ions on plasma facing components as well as for the development of diagnostics of fast ion losses [1, 2]. The present paper develops a Fokker-Planck approach for the assessment of the distributions of collisional loss of fast ions as depending on the coordinates of the first wall surface and on the velocities of lost ions. It extends former Fokker-Planck treatments of the poloidal distributions of fast ion loss induced by Coulomb collisions [3-5] to an arbitrary shape of the first wall and accounts for the effects of finite gyroradius. Based on this newly developed Fokker-Planck approach the poloidal distribution of neoclassical loss of fusion alphas in ITER will be examined. It is pointed out that the loss distributions obtained with the novel Fokker-Planck treatment will be useful for the verification of Monte-Carlo models [6, 7] used for simulating fast ion loss from toroidal plasmas. [1] FASOLI, A., et al., Nucl. Fusion 47 (2007) S264 S284 [2] KIPTILY V.G et al, Nucl.Fusion 65 (2009) [3] PUTVINSKII S.V., Alpha Particles in Tokamaks, in Rev. of Plasma Physics edited by B.B. Kadomtsev, vol. 18, Consultant Bureau, NY, [4] YAVORSKIJ, V., et al., EPS 2012, paper P1.144 [5] YAVORSKIJ., V.A. et al., Nucl. Fusion 43, 1077 (2003) [6] KURKI-SUONIO, T., et al., Nucl. Fusion 49 (2009) [7] SHINOHARA, K., et al., Nucl. Fusion 51 (2011)

53 P-6: the effect of perturbed electric fields and atomic processes on the redistribution of energetic particles R. Farengo 1, C. Clauser 2, I. Montellano 3, P. García-Martínez 2, H. Ferrari1 2, L. Lampugnani 2 1 Comisión Nacional de Energía Atómica, Centro Atómico Bariloche, Bariloche, Argentina. 2 CONICET, Bariloche, Argentina. 3 Instituto Balseiro, Bariloche, Argentina. The effect of the electric field due to mode rotation on the redistribution of high energy ions is studied. Two different scenarios are considered: α particles in an ITER like device and beam ions in an ASDEX-U like tokamak. We have already shown [1] that the perturbed electric field (E1) can have a large effect on the redistribution of α particles. Additional results, comparing different methods of calculating E1 will be presented. In recent numerical studies of the effect of (2,1) modes on the redistribution of beam ions [2,3] the use of a static magnetic perturbation is justified by noting that the transit frequencies of the ions are much higher than the mode frequency. We show that trapped particles, which have a bounce frequency lower than the toroidal transit frequency, can be significantly affected by the E1. Fig. 1 shows the effect of E1 on an 80 kev trapped ion for the conditions reported in [2] (two mode periods shown). This could explain the large peak in ion losses at a 45 pitch (trapped particles) seen in the experiments and not reproduced in the simulations [2]. Various mechanisms for anomalous α particle diffusion have been considered: large scale MHD fluctuations, microturbulence and toroidal ripple. We show that processes that change the charge of the α particles can also produce significant diffusion. Initial results show that for typical plasma parameters (n=1014 cm-3, T=10 kev) and a 1% neutral density, a 1 MeV α particle diffuses much faster due to charge exchange processes than to classical collisions. This effect will be important near the plasma edge and in the SOL, and should therefore be included in calculations of the alpha particle flux reaching the wall or divertor plates. Fig. 1. (a) Unperturbed orbit. (b) With a static magnetic perturbation. (c) With perturbed electric and magnetic fields. [1] R. Farengo, H. E. Ferrari,P.L. Garcia-Martinez, M.-C. Firpo, W. Ettoumi and A. F. Lifschitz. Phys. Plasmas 21, (2014). [2] M. García-Muñoz, P. Martin, H.-U. Fahrbach, M. Gobbin, S. Günter, M. Maraschek, L. Marrelli, H. Zohm and the ASDEX Upgrade Team. Nucl. Fusion 47, L10 (2007). [3] E Strumberger1, S Günter, E Schwarz, C Tichmann and the ASDEX Upgrade Team. N. Jour. of Phys. 10, (2008). 53

54 P-7: studies of fast ion losses caused by mhd instabilities by using faraday cup type lost ion probe in heliotron j plasmas S. Yamamoto 1, T. Sano 2, Y. Nakayama 2, K. Ogawa 3,4, M. Isobe 3,4, S. Kobayashi 1, T. Mizuuchi 1, K. Nagasaki 1, H. Okada 1, T. Minami 1, S. Kado 1, S. Ohshima 1, Y. Nakamura 2, S. Konoshima 1, L. Zang 1, G.M. Weir 1, N. Kenmochi 2, Y. Ohtani 2 and F. Sano 1 1 Institute of Advanced Energy, Kyoto University, Gokasho, Uji , Japan 2 Graduate School of Energy Science, Kyoto University, Gokasho, Uji , Japan 3 National Institute for Fusion Science, Oroshi-cho, Toki , Japan 4 SOKENDAI (The Graduate University for Advanced Studies), Toki , Japan of Submitting Author: yamamoto.satoshi.6n@kyoto-u.ac.jp For the purpose of clarification on a mechanism of interplay between fast ions and fast ion driven MHD instabilities, we have developed a Faraday cup type lost ion probe (FLIP) in Heliotron J, which is the medium size (R ~ 1.2 m/<a> < 0.2 m) Stellarator/Heliotron and has low magnetic shear in a whole plasma region. The FLIP is composed of eight thin aluminium plates as electrode and can detect lost ions having energy of E = 2 ~ 45 kev for hydrogen and pitch angle of χ = 90 ~ 150 deg. corresponding to co-going ions, respectively. Energetic particle modes (EPMs) and/or global Alfvén eigenmodes (GAEs) are observed in the Heliotron J plasmas which are heated by tangential co- and counter- injection of NB with energy of Einj < 27 kev. The increases in lost ion flux synchronized with the bursting EPMs, which have intense magnetic fluctuation and frequency chirping up and/or down, are observed in the two electrodes with E = 20 ~ 45 kev/ = 100 ~ 114 deg. and E = 2 ~ 12 kev/χ = 90 ~ 120 deg.. Full orbit calculation indicates that the detected ions should originate from plasma peripheral region where the observed EPMs are locally excited. Amount of lost ion flux is proportional to magnetic fluctuation amplitude of the EPMs. These results show that convective loss of ion is induced by EPMs in NBI-heated Heliotron J plasmas. 54

55 P-8: simulation study of triton confinement and nuclear reaction in the deuterium plasma experiment at lhd M. Homma, S. Muramkami, M.Isobe 1,H. Tomita 2 and K. Ogawa 1 Department of Nuclear Engineering, Kyoto University 1 National Institute for Fusion Science 2 Department of Quantum Engineering, Nagoya University Address of Submitting Author: homma@p-grp.nucleng.kyoto-u.ac.jp Deuterium plasma experiment campaign from 2017 is planned in the Large Helical Device (LHD). In deuterium discharges, tritons (1.01 MeV) and neutrons (2.45 MeV) are produced by fusion reactions between deuterium Neutral Beam Injection (NBI) beams and deuterium thermal ions. Understanding the behavior of energetic tritons would make it possible to experimentally study energetic particle confinement in future reactors. These experiments have been performed in JT-60U [1] known as triton burn-up experiments. In this study, confinement of energetic tritons for the LHD deuterium plasma is investigated using the GNET (Global NEoclassical Transport) code [2], in which the drift kinetic equation (DKE) of energetic particles is solved in five-dimensional phase space. GNET is also applied to evaluate the source profile of the tritons solving the DKE for NBI beam ions. The velocity distributions of energetic tritons are evaluated over a range of minor radii, and we present the characteristics of the triton distribution in velocity space. Next, we calculate D-T nuclear reaction rates using the obtained velocity distribution of tritons and simulate the signals of the neutron measurement systems in the D-D experiments on LHD. [1] T. Nishitani et al., Plasma Phys. Control. Fusion 38, 355 (1996). [2] S. Murakami et al., Nucl. Fusion 40, 693 (2000). 55

56 P-9: effect of high-z impurity on the nbi beam ion distribution and heat deposition in the lhd plasma H. Yamaguchi and S. Murakami Department of Nuclear Engineering, Kyoto University, Kyoto, Japan Address of Submitting Author: In the Large Helical Device (LHD) the high ion temperature is obtained by the carbon pellet injection[1] and high ion temperature experiments have been performed with the neon and argon gas puffing [2]. In high-z plasmas, heat deposition of NBI heating per ion is expected to be larger than in pure hydrogen plasma because of high Zi 2 /Ai of impurity ions and lower ion density. On the other hand, pitch-angle scatterings with high-z impurity ion can degrade the confinement of NB-born fast ions. In order to elucidate effect of impurity seeding in NBI heating in LHD plasmas, NBI heating analysis taking into account complex drift orbit and collisions with impurity ions is necessary. However, detailed analysis of fast ion confinement and heat deposition of NBI heating in such high-z plasmas of LHD is still not yet done. In this study, we perform NBI heating simulations in high-z impurity plasmas of LHD, using the GNET code [3] based on Monte Carlo method. We solve a drift kinetic equation for NB-born fast ions in five-dimensional phase space, taking into account pitch-angle- and energy scatterings as well as energy slow down. Complex guiding-center motion in the three dimensional magnetic configuration of LHD is followed in Boozer coordinates. We examine fast ion birth, confinement and heat depositions in high-z plasma of LHD and discuss the effect of high-z impurities on the NBI beam ion distribution and heat depositions in LHD plasmas. [1] H. Takahashi et al., Nucl. Fusion 53, (2013) [2] Y. Takeiri et al., Nucl. Fusion 47 (2007) [3] S. Murakami et al., Nucl. Fusion 40,693 (2000) 56

57 P-10: development of nonlinear collision operator for the monte carlo simulation code in toroidal plasmas S. Murakami, Y. Masaoka, H. Yamaguchi, M. Homma and A. Fukuyama Department of Nuclear Eng., Kyoto Univ., Nishikyo Kyoto , Japan Address of Submitting Author: In a D-T fusion plasma α-particles (E =3.5MeV) are generated by the fusion reaction and those α-particles mainly collide only with electrons because of very high velocity compared to the thermal ion ones. Thus it is considered that the pitch angle scattering is very small for the α-particle during the energy slow down. On the other hand, if we consider the relative velocity between the α -particles this relative velocity sometimes becomes very small. In this case they would experience an additional pitch angle scattering. Although the density of high-energy particle is much less than that of thermal other ions, the collisions between α-particles would have some effect on pitch angle scattering. This nonlinear collision effect may lead to deteriorate the α-particle confinement, because of increase of pitch angle scatterings. Thus, the analysis including the both complicated orbit and the nonlinear collisions are necessary to make clear the α-particle confinement in toroidal plasmas. However, the nonlinear collision operator has not yet been formulated for the orbit following type of Monte Carlo code. We have developed the nonlinear collision operator, which can be easily implemented to the for the Monte Carlo simulation code such as GNET [1,2]. In the previous papers [3,4] we have formulated the nonlinear collision operator and have shown that the newly developed nonlinear collision operator becomes the same formulation when we assume a Maxwellian background plasma. In this study we benchmark our collision operator model with the Fokker-Planck code, TASK/FP. TASK/FP include the nonlinear collision operator but the finite orbit effect cannot be included. So we benchmark the nonlinear collision operator assuming no orbit effect. Then we will study the effect of nonlinear collisions on the energetic particles confinement assuming a simple tokamak configuration. [1] S. Murakami et al., Nucl. Fusion 40, 693 (2000). [2] S. Murakami, et al. Nucl. Fusion 46, S245 (2006). [3] Y. Masaoka and S. Murakami, Plasma Fusion Res. 8, (2013). [4] S. Murakami et al., Proc. 41st EPS Conf. Plasma Phys. 2014, Berlin, P4.013 (2014). 57

58 P-11: numerical and experimental study of the redistribution of energetic and impurity ions by sawteeth in asdex upgrade experiments F. Jaulmes 1, B. Geiger 2, T. Odstrčil 2, M. Weiland 2, M. Salewski 3, A.S. Jacobsen 3, E. Westerhof 1 and the ASDEX Upgrade team 1 FOM Institute DIFFER Dutch Institute For Fundamental Energy Research, The Netherlands 2 Max-Planck-Institute for Plasma Physics, Boltzmannstr. 2, Garching, Germany 3 Technical University of Denmark, Department of Physics, Dk-2800 Kgs. Lyngby, Denmark Address of Submitting Author: F.Jaulmes@differ.nl During sawtooth crashes, fast ions are redistributed according to a complex motion with respect to the dynamics of the perturbed electromagnetic fields [1]. We discuss here the modelling of the sawtooth reconnection as well as the trajectories of the ions: an experimental validation of the modelling is given according to results from the ASDEX Upgrade experiment. The array of the soft-x-ray diodes in ASDEX Upgrade allows for a good time-resolved tomographic measurement of radiation emission during the sawtooth crash. Correspondingly, applying the odelling of the sawtooth to a population of thermal tungsten impurity ions allows for the reconstruction of the tungsten density evolution during the sawtooth crash. This reconstruction is in turn compared with the tomographic reconstruction of the soft-x-ray. Having assessed the dynamics of the sawtooth crash modelling on thermal tungsten ions give confidence to apply it to the fast ions: we thus simulate a population representative of a realistic Neutral Beam Injection (NBI) ions distribution in the geometry of the ASDEX Upgrade tokamak. The initial spread of the NBI ions is provided first according to TRANSP simulations and also by qualitatively trying to match tomographic data from the complete FIDA system. The validation of our orbit-following code EBdyna_go [1] is done by comparing the experimental signals from the Fast Ion D-Alpha diagnostic (FIDA) with simulated signals from the post-crash simulations. Further we compare the FIDA velocity-space tomographies in the plasma center with the EBdyna_go simulations before and after a sawtooth crash. The resulting comparison yields a good agreement between the simulation and the experimental data. In particular, a stronger redistribution of the higher-energy passing NBI ions is observed. This is encouraging for further comparison in dedicated experiments that will in turn study the peculiar effect of the sawtooth on populations of fast trapped ions such as the one generated by Ion Cyclotron Resonance Heating systems. References [1] F. Jaulmes, E Westerhof and H. J. de Blank, Nuclear Fusion 54 (2014), volume 10,

59 P-12: effect of the european design of tbms on iter wall loads due to fast ions in the baseline (15MA), hybrid (12.5MA), steady-state (9MA) and half-field (7.5MA) scenarios T. Kurki-Suonio 1, S. Äkäslompolo 1, K. Särkimäki 1, S. Sipilä 1, J. Varje 1 O. Asunta 1, and M. Gagliardi 2 1 Aalto University, Espoo, Finland 2 F4E, Barcelona, Spain The new physics introduced by ITER operation, of which there is very little prior experience, is related to the very energetic (3.5 MeV) alpha particles produced in large quantities in fusion reactions. These particles not only constitute a massive energy source inside the plasma, but also present a potential hazard to the material structures that provide the containment of the burning plasma. In addition, the negative neutral beam injection (NBI) produces 1 MeV deuterons which have to be well confined to ensure successful operation of ITER. The almost perfect confinement of energetic ions, predicted for axisymmetric tokamak configurations, can be compromised by a variety of components breaking the axisymmetry: the finite number and limited toroidal extent of the toroidal field (TF) coils (18 in ITER) cause a periodic magnetic field perturbation with a magnitude exceeding 1% at the separatrix. This magnetic ripple can cause significant fast particle leakage, leading to localized power loads on the walls. Therefore, ferromagnetic inserts (FI) will be embedded in the double wall structure of the ITER vacuum vessel, reducing the ripple to 0.6% everywhere else except near the NBI ports, where the ports interfere with the FI structures. The ITER magnetic field at the edge is further perturbed by the test blanket modules (TBM), made of ferromagnetic material and installed to test tritium breeding. TBMs cause poloidally and toroidally localized perturbations to the magnetic field. Consequently, the ITER field structure at the edge is quite complex, and studying its effect on fast ion confinement analytically is impossible. In this contribution, we calculated the ITER 3D magnetic field including the effects of the ferritic components (FIs and TBMs). The components were modelled with unprecented detail as energetic ions are very sensitive to magnetic field structure and, therefore, even small details in the field could have a significant effect on fast ion losses. The FEM solver COMSOL was used to first calculate the magnetization of the ferromagnetic components due to plasma current and currents flowing in the field coils. The perturbation field due to the magnetization was then calculated and added to the unperturbed field integrated from the coils using the Biot-Savart law. We simulate the fast ion wall power loads using the Monte Carlo orbit-following code ASCOT in the full 3D magnetic configuration. The first wall model also has full 3D features. The simulations are carried out for all the foreseen operating scenarios of ITER: the baseline 15 MA standard H-mode operation, the 12.5 MA hybrid scenario, the 9 MA advanced scenario, and the half-field scenario with helium plasma that will be ITER s initial operating scenario. Both thermonuclear fusion alphas and NBI ions from ITER heating beams are addressed. The alpha population is generated according to the fusion reactivity, given by the density and temperature profiles corresponding to the stationary phases of the ITER plasmas, while the NBI population is generated from beamlets that correspond to the injector s geometry. The ferritic components are found not to jeopardize the integrity of the first wall, but application of NBI in the ramp-up phases can lead to unacceptable shine-through. 59

60 P-13: comparison of fast ion confinement during on-axis and off-axis neutral beam experiments on nstx-u D. Liu,W. W. Heidbrink, G.Z. Hao University of California, Irvine, Irvine, CA 92697, USA M. Podesta, D. S. Darrow, E. D. Fredrickson, and S. S. Medley Princeton Plasma Physics Laboratory, Princeton, NJ 08543, USA A second more tangential neutral beam injector (NBI) is a major upgrade component of the National Spherical Torus Experiment Upgrade (NSTX-U) facility with the purpose of improving NBI current drive efficiency and providing more flexibility in the control of current and pressure profile. Good fastion confinement is essential to achieve the anticipated improvements in performance. After the completion of upgrade construction of NSTX-U this summer, a sanity check experiment will be performed to characterize the confinement and fast ion distribution function produced by this new offaxis and the existing on-axis NBI lines, and to compare them with classical predictions through NUBEAM modeling. In the sanity check experiment, various short (~20ms) and relatively long (~90ms) neutral beam pulses from different on-axis and off-axis neutral beam sources will be injected into quiescent L-mode discharges, which are optimized for accurate neutron, Fast-Ion D-Alapha (FIDA) and Solid State Neutral Particle Analyzer (SSNPA) measurements. The neutron rate decay after the turnoff of short neutral beam pulses will be used to estimate the fast ion confinement time and to investigate its dependence on neutral beam source/geometry, injection beam energy, plasma current and magnetic field. A slowing-down fast ion distribution and spatial profile during the injection of relatively long neutral beam pulses will be measured with FIDA and SSNPA diagnostics and compared with classical predictions through NUBEAM and FIDAsim modeling. Also, fast ion prompt losses in all conditions will be monitored with a scintillator Fast Lost Ion Probe (sflip) diagnostic. The experimental techniques, measurements of fast ion confinement and distribution function during on-axis and off-axis neutral beam experiments, and comparisons with NUBEAM modeling will be presented in detail. Work supported by U.S. DOE DE-AC0209CH11466, DE-FG02-06ER54867, and DE-FG03-02ER

61 P-14: numerical investigation of fast ion losses induced by resonant magnetic perturbations and edge localized modes at asdex upgrade M. Nocente 1, M. Garcia-Munoz 2,3, N. Lazanyi 4, M. Dunne 3, J. Galdon-Quiroga 2, M. Hoelzl 3, M. Rodriguez-Ramos 2, L. Sanchis-Sanchez 2, E. Strumberger 3, WP15-ER/IPP-05 Contributors and the ASDEX Upgrade Team 1 Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano-Bicocca,Piazza della Scienza 3, 20126, Milano, Italy 2 Department of Atomic, Molecular and Nuclear Physics. University of Sevilla. Spain 3 Max-Planck-Institut für Plasmaphysik, Garching, Germany 4 BME NTI, Pf 91, H-1521 Budapest, Hungary of Submitting Author: massimo.nocente@mib.infn.it A recent addition to the field of investigation on Edge Localised Modes (ELMs) has been the observation that fast ion losses can occur even when the ELMs are mitigated by means of resonant magnetic perturbations (RMPs) [1]. Such additional losses of energetic particles represent an added threat for machine protection and need to be understood and, eventually, controlled. In this contribution we present the results of a numerical study aimed at unveiling the principle mechanisms responsible for the observed losses at ASDEX Upgrade. Collisionless simulations of the beam ion orbits in a realistic three-dimensional, perturbed magnetic equilibrium were performed by means of the GOURDON code. In the presence of RMPs, these were used especially to calculate geometrical resonances between the orbital frequencies of the beam ions and to evaluate their role in the loss mechanism. A class of trapped particles exploring the entire pedestal and scrape off layer is found to satisfy geometrical resonance conditions. Compared to non resonant particles, ions fulfilling geometrical resonances can experience increased losses, but also - quite surprisingly - enhanced confinement, depending on their toroidal turning point location. Starting from these results, calculations of fast ion losses in the case of a rigid or differential rotation of the RMPs to mitigate first wall heat loads are presented and compared to recent experimental findings [2]. In the case of unmitigated ELMs, realistic JOREK [3] calculations of the magnetic equilibrium of a full ELM cycle were used as input for the simulations. Similarly to experiment, GOURDON results show a filamentary temporal pattern for the losses, with maxima corresponding to characteristic structures appearing beyond the last closed flux surface of the magnetic equilibria. Unlike experiment [2], however, the predicted phase space structure of the unconfined ions does not show particles at pitch angles different from those observed in the case of prompt losses. Motivations behind such discrepancy are illustrated and possibilities for simulation improvements are discussed. [1] M. Garcia-Munoz et al Nucl. Fusion [2] Lazanyi N. et al. this meeting [3] Hölzl M. et al Phys. Plasmas

62 P-15: Pressure anisotropy and flow suppress diamagnetic holes in high-beta tokamaks B. Layden, 1, M. J. Hole, 1 and R. Ridden-Harper 2 1 Research School of Physics and Engineering, The Australian National University, Acton ACT 2601, Australia 2 Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand Address of Submitting Author: brett.layden@anu.edu.au Increasingly high beta values are being obtained in modern high-performance tokamaks, with the Component Test Facility and Spherical Tokamak Power Plant concept devices projected to achieve volume-averaged toroidal betas of 30% and 60% respectively. At still higher beta, such that βq 2 ε 2 where ε is the inverse aspect ratio, analytical studies have shown that fundamental changes to the equilibria occur, the most striking for static equilibria being the formation of a field-free region called a diamagnetic hole. In recent work, Fitzgerald et al. (2011) showed that sufficiently high toroidal flow speeds (u u c ) suppress the diamagnetic hole. Such flows can be induced by auxiliary heating processes such as neutral-beam injection (NBI), which also generate significant pressure anisotropy. However, the effect of pressure anisotropy (and its combined effect with flow) on high-beta equilibria had not been investigated. We extend the work of Fitzgerald et al. to include both toroidal flow and pressure anisotropy. The force-balance model is based on guiding-centre plasma theory for a bi- Maxwellian distribution and the ideal MHD Ohm s law. We find that pressure anisotropy with p > p (p < p ) reduces (enhances) the plasma diamagnetism relative to the isotropic case whenever an equilibrium solution exists, which occurs if and only if the firehose (mirror) stability criterion is satisfied. We find that all firehose-stable solutions for p > p suppress the diamagnetic hole. For the no-flow case studied, plasmas with p /p > α 1 = 1.01 are firehose stable. The stability threshold α 1 decreases with increasing toroidal flow, and above the flow threshold u c we find α 1 = 0, so that all p > p equilibria are firehose stable. Parallel heating processes such as tangentially-oriented NBI are thus highly effective in suppressing the diamagnetic hole. On the other hand, for p < p there are no mirror-stable solutions below the flow threshold u c. Above this flow speed (where the diamagnetic hole no longer exists in the isotropic case), mirror-stable solutions exist for p /p > α 2, where α 2 decreases from unity with increasing flow above threshold. Toroidal flow therefore improves mirror-stability for high-beta plasmas with perpendicular heating such as perpendicularly-oriented NBI and ICRH. 62

63 P-16: investigation of fast ion behavior using orbit following monte-carlo code in magnetic perturbed field in kstar Kouji Shinoharaa 1, Junghee Kim 2,3, Jun Young Kim 3, YoungMu Jeon 2, and Yasuhiro Suzuki 4 1 Japan Atomic Energy Agency, Naka, Ibaraki , Japan 2 National Fusion Research Institute, Daejeon, Korea 3 University of Science and Technology, Daejeon, Korea 4 National Institute for Fusion Science, Toki, Gifu, Japan Address of Submitting author: shinohara.koji@jaea.go.jp The effect of the ELM coil field in the ITER on fast ions was studied by using the OFMC code [1]. The studies revealed that ELM coil field could deteriorate fast ion confinement or increase heat load on the divertor and its non-heat-resistance components. The studies were based on the calculation using the socalled vacuum field, which was produced by the ELM coil alone. However, it is considered that the externally applied ELM coil field could be affected by the plasma response. In the perturbed filed affected by the plasma response, the knowledge on fast ion behavior is limited to specific cases. It is interesting to know how the plasma response changes the perturbed field and its effect on fast ion behavior. One of the important fast ion responses to be investigated is the heat load, especially localized heat load, on plasma facing components (PFCs). The heat load studies indicated the 3D dependence of the heat load on the 3D shape of PFCs as well as the 3D nature of a magnetic field [2]. In this presentation, as case studies, we compare the fast ion behavior and heat load on the PFCs in various magnetic field, including the case where the plasma response is taken into account, in an actual geometry using the KSTAR device. The magnetic field with the plasma response is calculated by using HINT2 code [3]. The change in magnetic field structure was observed depending on the kinetic plasma profile. The heat load distribution was changed responding to the change in the field structure. This suggests the predicition of heat load in the RMP experiments in ITER is not easy since the magnetic field perturbation depends on plasma parameters in a discharge. The protection of the non-heat-resistance components is recommended in ITER. The heat load in the divertor region is not large in the case of KSTAR in contrast to ITER. The most loss particles hit the limiter structure. We will report the results of the calculations. [1] Tani K., et.al., NF 52 (2012) ; Shinohara K., et.al., NF 52 (2012) ; Oikawa T., et.al., in Proceedings of the 24th IAEA Fusion Energy Conference (2012) [2] Shinohara K., et.al., NF 43 (2003) 586; M. Garcia-Munoz, et.al., PPCF 55 (2013) ; M. A. Van Zeeland et al., PPCF 56, (2014) [3] Suzuki Y., et al., NF 46 (2006) L19 63

64 P-17: fast particle physics and its connection to performance on c-2 N.G. Bolte, M.W. Binderbauer, T. Tajima, A. Smirnov, R. Clary, B.H. Deng, H. Gota, D. Gupta, S. Korepanov, R. Magee, M. Thompson, E. Trask, M. Tuszewski, K. Zhai Tri Alpha Energy, Inc. Address of Submitting Author: Conventional field-reversed configurations (FRCs) high-beta, prolate compact-toroids embedded in poloidal magnetic fields face notable stability and confinement concerns. These can be ameliorated by various control techniques, such as introducing a significant fast-ion population. Indeed, adding neutral beam injection into the FRC over the past half-decade has contributed to striking improvements in confinement and stability. Neutrons studies show that superthermal ions slow down and diffuse classically. Fast-ion pressure is shown to increase in time and with increased neutral-beam power and becomes equal to thermal plasma pressure under full beam power. Further, the addition of electrically biased plasma guns at the ends, magnetic end-plugs, and advanced surface conditioning leads to a dramatic reduction in losses and greatly improves stability. The n=2 mode is shown to be significantly reduced with increasing neutral-beam power and/or increased plasma gun voltage. Broadband magnetic fluctuations also decrease with increasing beam power. All together, these factors enable the build-up of a well-confined and dominant fast-ion population. Under such conditions, highly reproducible, macroscopically-stable and hot FRCs (with total plasma temperature of ~ 1 kev) with record lifetimes are achieved. These accomplishments point to the prospect of advanced, beam-driven FRCs as an intriguing path toward fusion reactors. 64

65 Frequency (khz) P-18: fishbone activity in east neutron beam injection plasma Liqing Xu 1, Jizong Zhang 1, Kaiyun Chen 1, Liqun Hu 1, Erzhong Li 1, Shiyao Lin 1, Tonghui Shi 1, Neng Pu 1, Yanmin Duan 1, Yubao Zhu 2, Xiuli Sheng 1 and Jinlong Zhao 1 1 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei , China 2 Department of Physics and Astronomy, University of California, Irvine, California , USA Repetitive fishbones near the trapped ion processional frequency was observed for the first time in the neutron beam injection (NBI) high confinement plasmas in EAST tokamak,diagnosed using a newly developed compact silicon photodiode based solid state neutral particle analyzers (ssnpa) together with an upgraded high spatial-temporal-resolution multi-arrays soft x-ray (SX) system. This 1/1 typical internal kink mode travels with a rotation speed faster than the bulk plasma in the plasma frame. This mode frequency shows the nature of typical frequency chirping down, as evidenced by SX measurements. It is found that this ion fishbone can trigger core sawtooth crash, multiply with edge 2/1 sideband mode as well as lead to a fishbone-long lived saturated kink mode (LLM)-fishbone transition. Furthermore, by means of SX tomography, a correlation between the mode amplitude and the mode frequency was found f 4kHz f fb ( ) 1.25 khz Core ArXVII,q= Time/s Typical frequency whistling down spectrograms of fishbone as observed from a central SX channel together with the central bulk plasma rotation speed (blue star) measured by x-ray crystal spectrometer. 65

66 P-19: progress in gyrokinetic particle simulation of Alfvén instabilities Z. Lin University of California, Irvine, California 92697, USA This paper reports recent progress in global gyrokinetic particle simulation of Alfven instabilities excited by energetic particles (EP) in fusion plasmas, in particular, the nonlinear saturation of toroidal Alfven eigenmode (TAE) by zonal fields and the excitation of beta-induced Alfven-acoustic eigenmode (BAAE) by EP. TAE saturation by zonal fields-- GTC simulations 1,2 of TAE in DIII-D shot # near 525ms have been extended to nonlinear regime to test effects of EP nonlinearity, thermal plasma nonlinearity, and zonal fields (zonal flow and zonal current). When only EP nonlinearly is kept in the simulation (green line in figure), TAE saturates at a high amplitude due to the relaxation of EP density profiles. When thermal plasma nonlinearity is added in the simulation (red line), TAE saturates at a lower amplitude, indicating the importance of the thermal plasma nonlinearity. Finally, when zonal fields are self-consistently kept in the simulation (blue line), TAE saturates at a much lower amplitude and there is little relaxation in EP density profiles. The TAE mode structures are somewhat distorted by the zonal flow. The effects of zonal fields are mostly by the zonal flow, similar effects are observed in the nonlinear saturation of beta-induced Alfven eigenmode (BAE) 3. Suppressing zonal current causes little difference in the TAE saturation amplitude. The collisionless skin depth effects likely suppress the modulational instability. The zonal field generation is thus via mode coupling, similar to earlier MHD-gyrokinetic simulations. The growth rate of zonal fields is slightly less than twice of TAE growth rate, indicating some damping of the zonal fields by thermal plasmas. BAAE excitation by EP -- The existence of BAAE in toroidal plasmas is verified by GTC simulations. In the Ti Te limit, where the BAAE is weakly damped, the existence of BAAE is verified in simulations using initial perturbation, antenna excitation, and energetic particle excitation, respectively. The damping rate of the BAAE is comparable to the real frequency in simulations with more realistic Ti~Te for both reversed shear and monotonic q profiles. Surprisingly, the BAAE can be easily excited by modest EP density gradient due to the formation of the well-behaved eigenmode structure, which is very different from the singular structure of the heavily damped quasimode. The BAAE mode structure in the reversed shear q profile has opposite triangle shape compared to the monotonic q profile. The frequency sweeping of the BAAE is observed in the reversed shear q profile, but not in the monotonic q profile. In collaboration with SciDAC GSEP Center and GTC Team. 1. Radial Localization of Toroidicity-Induced Alfven Eigenmodes, Zhixuan Wang, Zhihong Lin, Ihor Holod, W. W. Heidbrink, Benjamin Tobias, Michael Van Zeeland, and M. E. Austin, Phys. Rev. Lett. 111, (2013). 2. Properties of Toroidal Alfven Eigenmode in DIII-D Plasma, Z. X. Wang, Z. Lin, W. J. Deng, I. Holod, W. W. Heidbrink, Y. Xiao, H. S. Zhang, W. L. Zhang, M. A. Van Zeeland, Phys. Plasmas 22, (2015). 3. Nonlinear generation of zonal fields by the beta-induced Alfven eigenmode in tokamak, H. S. Zhang and Z. Lin, Plasma Sci. Technol. 15, 969 (2013). 66

67 P-20: experimental investigation of elm-induced fast-ion losses at the asdex upgrade tokamak N. Lazányi 1, M. Garcia-Muñoz 2,3,4, M.Nocente 5, J. Galdon-Quiroga 2, M. Hoelzl 4, G. Por1, P. Poloskei 1, M. Rodriguez-Ramos 2,3, L. Sanchis-Sanchez 2, G.I. Pokol 1, the EUROfusion MST1 Team and the ASDEX Upgrade Team4 1 BME NTI, Pf 91, H-1521 Budapest, Hungary 2 Dept. of Atomic, Molecular and Nuclear Physics. University of Sevilla. Spain 3 CNA (U. Sevilla, CSIC, J. de Andalucia). Spain 4 Max-Planck-Institute für Plasmaphysik, Garching, Germany 5 Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano-Bicocca,Piazza della Scienza 3, 20126, Milano, Italy Address of Submitting Author: lazanyi.nora@reak.bme.hu Edge localized modes (ELMs) are inherent instabilities of H-mode plasmas and are observed causing fast-ion losses [1]. The lost fast ions can be measured by a scintillator-based fast-ion loss detector (FILD) [2], which works as a magnetic spectrometer and sorts the fast ions by their gyroradius and pitch angle relative to the local magnetic field lines in front of the detector. The detectors are equipped with CCD/CMOS cameras observing the whole scintillator (velocity-phase space) and photomultiplier tubes (PMTs), which are integrating regions of the scintillator, but their high sampling rate makes them capable to detect high frequency fluctuations in the losses. An overview of the internal structure of the observed ELM-induced fast-ion losses is given, and the losses have been analysed both in time domain and in velocity-space based on the signal of the PMTs and camera images, respectively. The observed structures of the ELMinduced losses are qualitatively compared to GOURDON simulation results using magnetic equilibria of a full ELM cycle provided by the JOREK code [3]. The spatial structure of the modes corresponding to ELMs was also investigated. Internal MHD perturbations such as Neoclassical Tearing Modes (NTMs) are observed to change the measured ELM induced fast-ion losses. The counter-effect is also true with ELMs significantly affecting the observed NTM induced losses with islands localized in the outer mid radius. The impact that the interaction between ELMs and NTMs has on the temporal evolution of losses as well as on their velocity-space will be presented and discussed in light of the JOREK-GOURDON simulations. [1] M. GARCIA-MUNOZ et al., Plasma Phys. and Control. Fusion 55 (2013) [2] M. GARCIA-MUNOZ et al., Rev. Sci. Instrum. 80 (2009) [3] M. NOCENTE et al., same conference 67

68 P-21: analysis of icfr heating and icfr-driven fast ions in recent jet experiments M.J. Mantsinen 1, C. Challis 2, J. Eriksson 3, D. Frigione 4, J. Garcia 5, C. Giroud 2, T. Hellsten 6, A. Hjalmarsson 3, D.B. King 2, E. Lerche 7, M. Schneider 5, S. Sharapov 2 and JET contributors* EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK 1 ICREA-Barcelona Supercomputing Center, Barcelona, Spain 2 CCFE, Culham Science Centre, Abingdon, OX14 3DB, UK 3 Uppsala University, Department of Physics and Astronomy, Sweden 4 ENEA, Frascati, Italy 5 CEA, IRFM, Saint-Paul-lez-Durance, France 6 Dept. of Fusion Plasma Physics, EES, KTH, Stockholm, Sweden 7 Laboratory for Plasma Physics, LPP-ERM/KMS, Brussels, Belgium *See Appendix of F. Romanelli et al., Proc. 25th IAEA FEC 2014, Saint Petersburg, Russia Address of Submitting author: mervi.mantsinen@bsc.es Heating with waves in the ion cyclotron range of frequencies (ICRF) plays an important role in the operation and the performance optimization of several present-day experimental fusion devices. ICRF waves will also be used in ITER and are planned for the demonstration fusion power plant DEMO. For ITER, the main ICRF scenario is second harmonic heating of tritium which coincides with the fundamental minority heating of 3 He. For second harmonic heating of tritium, as for other harmonic ICRF heating schemes, the damping of the wave power is a finite Larmor radius effect. Therefore, its physics can be studied in a non-activated environment in the present day experiments using ICRF schemes involving second or high-harmonic damping. In the present paper, recent experiments in JET with ICRF heating are analyzed with the time-dependent ICRF modelling code PION [1] with special emphasis on the physics of higher harmonic ion cyclotron damping in preparation of ITER. In particular, we consider three different ICRF heating scenarios where second or higher harmonic damping has been observed to play an important role: (a) hydrogen minority heating, coinciding with second harmonic heating of deuterium beam ions, in high-performance JET hybrid discharges; (2) third harmonic heating of deuterium beam ions in experiments for fusion product studies [2] and (3) second harmonic heating of hydrogen in hydrogen plasmas. The experimental results are compared to modelling and overall, good agreement is found. This increases our confidence in the modelling of higher-harmonic ICRF heating schemes and, in particular, in the extrapolations of the performance of second harmonic ICRF heating of tritium in ITER and DEMO. [1] L.G. Eriksson, et al. Nucl. Fusion 33 (1993) [2] S. Sharapov et al., this conference. 68

69 P-22: a stability study of α-particle driven alfvén eigenmodes in jet d-t plasmas J. Ferreira 1, D. Borba 1, R. Coelho 1, L. Fazendeiro 1, A.C.A. Figueiredo 1, N. F. Loureiro 1, F. Nabais 1, P. Rodrigues 1, J. Conboy 2, M. Fitzgerald 2, S.E. Sharapov 2, I. Voitsekhovitch 3, and JET Contributors EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK 1 Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal 2 CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom, 3 EuroFusion Consortium Programme Unit, Boltzmannstr. 2, D-85748, Garching, Germany, Address of Submitting Author: Jorge.Ferreira@ipfn.tecnico.ulisboa.pt Given the unique capabilities of the Joint European Torus (JET) a campaign with deuterium-tritium (DT) plasmas is being planned in advance of ITER operations [1,2]. As a contribution to the preparation efforts, a tool that has recently been developed for the systematic linear-stability assessment of Alfvén eigenmodes in the presence of fusion born α-particles [3,4] is here applied to a representative set of JET DT scenarios. This study will allow us to better understand the impact of α- particles on Alfvén stability. Starting from a selected set of pulses [2] the equilibria and fast particle distributions are predicted through transport modelling using the numerical transport code TRANSP [5]. The Alfvén spectrum and its stability is computed using the ASPACK suite of codes [3,4], which includes the equilibrium solver HELENA [6], the ideal magnetohydrodynamic eigensolver MISHKA [7], and the linear-stability hybrid MHD/drift-kinetic numerical code CASTOR-K [8]. As a result of an extensive linear assessment of the growth rates for the Alfvén spectra of different DT scenarios due to driving interaction with α-particles and damping on thermal populations, the most unstable Alfvén eigenmodes are identified and their importance discussed. Other relevant mechanisms such as radiative and continuum dampings are also tackled and estimates are given. Acknowledgments IST activities received financial support from Fundação para a Ciência e Tecnologia through project UID/FIS/50010/2013. References [1] L. Horton and JET Contributors, 2015, 12 th International Symposium on Fusion Nuclear Technology, ICC JEJU, Jejun Island Korea, oral presentation. [2] S.E. Sharapov, I. Voitsekhovitch, et al., 2011, 38 th European Physical Society Conference on Plasma Physics, Strasbourg, France, P [3] P. Rodrigues et al., 2015, Systematic linear-stability assessment of Alfvén eigenmodes in the presence of fusion α-particles for ITER-like equilibria, submitted to Nuclear Fusion. [4] P. Rodrigues et al., 2014, Proceedings of the 25 th IAEA Fusion Energy Conference, Saint Petersburg, Russia, TH/P3-25, arxiv: [5] R. J. Goldston, D. C. McCune, et al., 1981, J. Comput. Phys. 43, p. 61. [6] G. Huysmans et al., 1991, Europhysics Conference on Computational Physics (World Scientific) p [7] A.B. Mikhailovskii et al., 1997, Plasma Phys. Rep. 23, p [8] D. Borba and W. Kerner, 1999, J. Comput. Phys. 153, p See the Appendix of F. Romanelli et al., Proceedings of the 25th IAEA Fusion Energy Conference 2014, Saint Petersburg, Russia 69

70 Poster Session II Thursday 3rd September, P-23 P. Puglia The JET Upgraded Toridal Alfven Eigenmode diagnostic system P-24 M. Hole Developments in advanced MHD Spectroscopy P-25 C. Ryu Particle in Cell Simulation of Toroidal Alfven Eigenmodes in KSTAR P-26 Z. Qu Flow enabled instabilities in energetic geodesic acoustic modes (EGAMs) P-27 Ph. Lauber Off-axis NBI-driven energetic particle modes at ASDEX Upgrade P-28 X. Du Resistive Interchange Mode destabilized by Helically Trapped Energetic Ions in LHD plasma P-29 V. Fusco Electron fishbone dynamic studies in tokamaks with the XHMGC code P-30 G. Fogaccia Linear benchmark between HYMAGYC and HMGC codes P-31 A. Stahl Kinetic modelling of runaway electron dynamic P-32 J. Huang Fast-Ion D-Alpha Spectrum during EAST neutral-beam heated plasmas P-33 V. goloborod ko Evaluation of fluxes of lost alphas for gamma-ray diagnostics in ITER P-34 V. Yavorskij Interpretive and predictive modelling of fluxes of charged fusion products lost from tokamak plasmas P-35 A. Sanyasi Diagnosis of Mirror Trapped Particles and Excitation of Energetic Particle (EP) Driven Modes in LVPD P-36 M. Nocente Diagnosing MeV range deuterons with neutron and gamma ray spectroscopy at JET P-37 L. Stagner A comparison of reconstruction methods for inferring the fast-ion distribution function from multiple FIDA measurements P-38 Y. Zhu Preliminary Results of the EAST Integrated Energetic Neutral Particle Analyzer and Its Conceptual Design on the HL-2A/M Tokamaks 70

71 P-39 S. Sharapov Fast Ion D-D and D-3He Fusion on JET P-40 K. Nagaoka Measurement of Phase Space Structure of Fast Ions Interacting with Alfven Eigenmodes P-41 J. Galdon Damage of Plasma Facing Components due to Fast-Ion Losses in the ASDEX Upgrade Tokamak P-42 M. Weiland Further acceleration of beam ions by 2nd harmonic ion cyclotron heating in ASDEX Upgrade I-6 G. Fu Stability and Nonlinear Dynamics of Beam-driven Instabilities in NSTX I-7 A. Biancalani Non-perturbative nonlinear interplay of Alfven modes and energetic ions I-8 Y. Kazakov Fast Ion Generation with Novel Three-Ion ICRF Scenarios: from JET, W7-X and ITER applications to aneutronic fusion studies I-9 X. Wang Structure of wave-particle interactions in nonlinear Alfvénic fluctuation dynamics I-10 A. Bierwage Alfven Acoustic Channel for Ion Energy in High-Beta Tokamak Plasmas I-11 M. Fitzgerald Predictive nonlinear studies of TAE-induced alphaparticle transport in the Q=10 ITER baseline scenario I-12 M. Cole Progress in non-linear electromagnetic gyrokinetic simulations of Toroidal Alfvén Eigenmodes 71

72 P-23: the jet upgraded toridal alfven eigenmode diagnostic system* P. Puglia 2, W. Pires de Sa 2, P. Blanchard 1, S. Dorling 4, S. Dowson 4, A. Fasoli 1, J. Figueiredo 5, R. Galvão 2, M. Graham 4, G. Jones 4, C. Perez von Thun 5, M. Porkolab 3, L. Ruchko 2, D. Testa 1, P.Woskov 3 and JET Contributors 6 EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK 1 Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH Lausanne, Switzerland 2 Instituto de Física, Universidade de São Paulo, São Paulo CEP ; Brazil 3 PSFC-MIT 4 CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom 5 EUROfusion PMU, Culham Science Centre, Abingdon, Oxon, OX 14 3DB United Kingdom 6 See the Appendix of F. Romanelli et al., Proceedings of the 25th IAEA Fusion Energy Conference 2014, Saint Petersburg, Russia Address of Submitting Author: paulogiovane@gmail.com The JET Toroidal Alven Eigenmode (AE) diagnostic system is undergoing a major upgrade to provide a state of the art excitation and real-time detection system for JET. Experimental measurements and studies of AE at JET have been done successfully first with the saddle coil system [1] and then with purpose built in-vessel antennas with real time mode tracking algorithm [2]. Complete new excitation and digital control system have been developed for this upgrade and are currently installed to provide JET with a unique diagnostic to study AE in DT experimental campaign and towards ITER. New exciters consisting of 4kW class D power switching amplifiers, one for each antenna, have been developed in collaboration with the industry to cover the frequency range of operation kHz with RF pulse duration of 15s and repeatability <15min. Due to the varying transmission line impedance throughout the frequency band, design solution with high resilience to reflected power was implemented with VSWR>>10:1. A complete new digital amplifier control system has been implemented based on FPGA modules for amplifier frequency and phase control with frequency resolution <1Hz and phase<0.3 degrees at 100kHz. Gain control along with timing, gating and trip management is done using RT LabView. New capabilities like independent antenna current and phase control will allow improved excitation control, better definition of antenna spectrum combined with enhanced system reliability. [1] Fasoli A. et al 1995 Phys. Rev. Lett ; [2] Testa D. et al 2004, Proc. 23rd Symp. on Fusion Technology *This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect those of the European Commission. The Brazilian group works under the Brazil EURATOM collaboration agreement, with support from FAPESP Project 2011/ The work of the US collaborators at MIT was supported by US DOE Grant DE-FG02-99ER This work was supported in part by the Swiss National Science Foundation. 72

73 P-24: Developments in advanced MHD Spectroscopy M.J. Hole 1, S. Cox 1, C. M. Ryu 2, M. H. Woo 3, K. Toi 4, J. Bak 3, S. Sharapov 5, M. Fitzgerald 1 1 Plasma Theory and Modelling Group, Australian National University, ACT 0200, Australia 2 POSTECH, Pohang, Korea. 3 National Fusion Research Institute, Daejon, Korea 4 National Institute for Fusion Science, GIFU Prefecture, Japan 5 EURATOM/CCFE Fusion Assoc., Culham Science Centre, Abingdon, Oxon OX14 3DB, UK matthew.hole@anu.edu.au We report on a range of wave activity observed during neutral beam heating in KSTAR plasmas, including BAE s, TAE s, and ion fishbones. A detailed analysis of 40 khz magnetic fluctuations with a toroidal mode number of n = 1 reveals a BAE resonant with the q = 1 surface. [1]. For this case, we have computed the threshold to marginal stability for a range of ion temperature profiles. These suggest the BAE can be driven unstable by energetic ions when the ion temperature radial gradient is sufficiently large. Figure 1 shows candidate ion temperature profiles with core temperature matching crystallography data from neighbouring discharge #4229, as well as the corresponding profile of η i /η ic, where is η ic is the critical value of η i = ( ln T i / ln n i ) necessary for ion thermal excitation. For sufficiently high radial temperature gradient and/or sufficiently high ion temperature, the Alfvénic ion temperature gradient driven mode instability threshold will be approached, or possibly even exceeded, in the region where the mode amplitude is large, and so the mode can become unstable, due to a combination of energetic and thermal ion kinetic effects. Our findings suggest that mode existence could be used as a form of inference for temperature profile consistency in the radial interval of the mode, thereby extending the tools of MHD spectroscopy. In unrelated work we also report on a linear inference technique we have developed recently infers changes in the ion slowing down distribution function from changes in neutron emission during fishbones, and has been applied to MAST data. [1] M J Hole et al, First evidence of Alfvén wave activity in KSTAR plasmas, Plasma Phys. Control. Fusion 55 (2013) Fig. 1: (a) Possible ion temperature profiles (solid) with core temperature matching crystallography data from discharge #4229, and (b) corresponding profile of η i /η ic. In both panels the dashed line corresponds to a possible Ohmic ion temperature profile, with τ=t e /T i taken from discharge #4229 prior to NBI heating. In (b) the light line is r of the BAE. 73

74 P-25: particle in cell simulation of toroidal alfven eigenmodes in kstar C. M. Ryu 1, H. Rizvi 1, and Z. Lin 2 1 POSTECH, Pohang, Korea 2 University of California, Irvine, CA 92697, USA Address of Submitting Author: ryu201@postech.ac.kr During the KSTAR campaigns, plasmas with currents up to Ip=600 ka and magnetic fields B=2-3T were made by using two neutral beams with energies of 80KeV and 90KeV, which induced fast particles with velocities around 2.7x10 6 m/s, and the Alfven velocity about V A = 1.5x10 7 m/s. In these shots, discrete stair-like modes are detected in Mirnov coil (MC)s at frequencies in the range of KHz. These modes are shown to much resemble the core localized TAEs observed in JET plasmas [1]. To characterize these modes, we have investigated the TAE excitation in KSTAR by using the gyrokinetic toroidal code (GTC) [2] with a numerical equilibrium generated by using EFIT for these shots. The critical plasma shear for these shots is s c =m 2 /(4n 2 q 2 ε)~0.74. Because the plasma shear is less than the critical shear ( s<s c ) in a rather wide range of r/a < 0.75 in KSTAR, discrete Alfven eigenmodes are expected to occur up to 3/4 radius of KSTAR plasmas [3]. Our GTC simulation shows that multiple m modes for fixed n are excited at about r/a=0.42 and 0.56 with frequencies khz, which are consistent with the experimental observation in KSTAR. Detailed analyses of GTC simulation results are presented. [1] N. P. Young, et. al. Plasma Phys. Control. Fusion 48 (2006) [2] Z. Lin, T. S. Hahm, W. W. Lee, W. M. Tang, and R. B. White, Science 281(1998) [3] J. Candy, B. N. Breizman, J. Van Dam, and T. Ozeki Phys. Lett. A 215(B1996)

75 P-26: flow enabled instabilities in energetic geodesic acoustic modes (egams) Zhisong Qu 1, Matthew Hole 1, Michael Fitzgerald 2 and Brett Layden 1 1 Research School of Physics and Engineering, the Australian National University, Canberra ACT 2601, Australia 2 EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB, UK Address of Submitting Author: zhisong.qu@anu.edu.au Energetic geodesic acoustic modes (EGAMs) 1,2 are axisymmetric energetic particle modes found in toroidally confined plasmas resulting from the geodesic curvature of magnetic field lines. They are experimentally observed at half of the conventional GAM frequency and are localized at the core, where there is a significant fast particle population. Until recently, it was widely believed that EGAMs are driven unstable by a positive gradient of the fast particles in the velocity space ( F/ E > 0). However, unlike previous studies * which treat fast ions kinetically, we consider the thermal ions and fast ions as different type of fluids with a super thermal flow speed for the latter. Surprisingly, the frequency and growth rate predicted by our fluid mode agree well with the kinetic theory within the region of validity of the fluid model, despite the absence of inverse Landau damping in the fluid model. This indicates that under some conditions, the EGAMs are not driven by wave-particle interaction, but are enabled by flow effects. As in previous studies, multiple branches of GAM solutions are found. The dependency of their frequencies on the q value, the beam transit frequency and the fast particle populations is examined. The application of our model in the early beam turn on of EGAMs in DIII-D is also discussed. 1 Nazikian, R. et al. Phys. Rev. Lett. 101, (2008). 2 Fu, G. Phys. Rev. Lett. 101, (2008). 3 Girardo, J.-B. et al. Phys. Plasmas 21, (2014). 75

76 P-27: off-axis nbi-driven energetic particle modes at asdex upgrade Ph. Lauber 1, B. Geiger 1, M. Maraschek 1, L. Horvath 2, C. Di Troia 6, G. Papp 1, M. Dunne 1, A. Biancalani 1, M. Schneller 1, X. Wang 1, I. Classen 4, V. Igochine 1, A. Mlynek 1, M. García-Muñoz 1 ; 1,5,V. Nikolaeva 1,3, L. Guimarais 3, NLED Enabling Research Team, and the ASDEX Upgrade Team 1 Max-Planck-Institut für Plasmaphysik, Garching, Germany Address of Submitting Author: pwl@ipp.mpg.de 2 Institute of Nuclear Techniques, BME, Budapest, Hungary 3 Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Tecnico, Universidade Técnica, Lisboa, Portugal 4 FOM Institute Differ - Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, 3430 BE Nieuwegein, The Netherlands 5 Department of Physics, University of Seville, Seville, Spain 6 ENEA, Frascati, Italy The off-axis injection of neutral beam ions (2.5 MW) during the current ramp-up phase in ASDEX Upgrade gives rise to strongly non-linear energetic particle bursts emerging from the TAE gap. The modes seem to be similar to observations on JT-60U [Shinohara, ] or on spherical tokamaks with the important difference that at ASDEX Upgrade the ratio of the velocity of injected beam ions compared to the Alfven velocity is far below 1(v NBI / v A ) ~ 0.4). The fast ion b in these discharges is transiently comparable or even larger than the thermal b allowing one to explore a unique parameter space relevant for the stability of burning plasmas. Additionally, a clear correlation of these bursts and energetic particle driven geodesic acoustic modes (EGAMs) is observed, indicating a velocity space coupling of both modes. Based on various diagnostics measurements and beam deposition calculations for the energetic particle distribution function, a kinetic stability analysis will be shown, investigating the drive mechanism of the EGAMs and the TAE bursts. The non-linear features of the modes will be discussed. More generally, these results will allow us to understand in a detailed way the transition from weakly-driven Alfvén modes to strongly-driven energetic particle modes and the interaction mechanisms of AEs with zonal modes, both experimentally and theoretically/numerically. Figure 1: Spectrogram of the magnetic pick-up coil signal in the presence of off-axis (co-direction) NBI drive (#31213). This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect those of the European Commission. 76

77 P-28: resistive interchange mode destabilized by helically trapped energetic ions in lhd plasma X.D. Du 1, K. Toi 2, S. Ohdachi 1,2, M. Osakabe 1,2, T. Ido 2, K. Tanaka 2, M. Yokoyama 1,2, M.Yoshinuma 1,2, K. Ogawa 2, K.Y. Watanabe 2, M. Isobe 1,2, K. Nagaoka 1,2, T. Ozaki 2, S. Sakakibara 1,2, R. Seki 2, A. Shimizu 2, Y. Suzuki 1,2, H. Tsuchiya 2 and LHD Experiment Group 1 The Graduate University for Advanced Study, Toki , Japan 2 National Institute for Fusion Science, Toki , Japan The resistive interchange mode (RIC) destabilized through resonant interaction with a characteristic motion of helically trapped energetic ions are observed in Large Helical Device (LHD), called the EIC, exhibiting bursting character and rapid frequency chirping down [1]. The initial frequency of the EIC is consistently explained by the mode-particle resonance condition in a non-axisymmetric LHD plasma. This resonant interaction is clearly found in the rapid changes in the energy spectra of charge exchanged neutral flux perpendicular to magnetic field line below the injected beam energy of 34keV. The mode structure has a quite similar eigenfunction of the radial displacement of the RIC. That is, the EIC is well localized at the mode rational surface, even if the EIC has low poloidal and toroidal mode numbers m = 1/n = 1, and the eigenfunction is an odd function indicating an island-type shape. The threshold of helically trapped energetic ions pressure is investigated, i.e., the volume averaged β h ~ 0.3% and that of local beta of ~ 0.2% at ι = 1 surface. The EIC also strongly impacts the confinement of helically trapped energetic ions and induces noticeable losses. The non-ambipolar radial transport of the helically trapped energetic ions is inferred from the large and sudden drop of plasma potential measured by the heavy ion beam probe and also from the sudden increase of charge exchanged neutral flux. In addition, the clear suppression of micro-turbulence measured by a CO2 laser phase contrast imaging is observed with each EIC burst. [1] X.D. Du, K. Toi, M. Osakabe et al., Phys Rev. Lett. 114, (2015) 77

78 P-29: electron fishbone dynamics studies in tokamaks with the xhmgc code V. Fusco, G. Vlad, S. Briguglio, G. Fogaccia ENEA for EUROfusion, Via E. Fermi 45, Frascati, Italy Address of submitting Author : valeria.fusco@enea.it The electron fishbone modes are internal kink instabilities induced by suprathermal electrons. Ion fishbones were first observed experimentally (PDX) [1], opening the path to full theoretical understanding of these phenomena [2]. Stimulated by experimental evidence of electron fishbones (DIII-D, Compass-D, FTU, ToreSupra), theoretical analysis has also been extended to the case of modes excited by fast electrons [3]. It is well known that additional heating of a plasma produces suprathermal particles which, under certain conditions, could destabilize symmetry breaking modes. Moreover, the dynamics of suprathermal electrons in present days experiments has analogies to that of alpha particles in future burning plasma devices; and resonant excitation by fast electron precession resonance may provide a good test bed for understanding the similar mechanism induced by fusion alphas. For these reasons, it is important to get insights into the underlying physics processes involved in these phenomena. In this work, numerical simulations with the HMGC code are systematically carried out in tokamak equilibria. On the one side, theoretical and experimental results are confirmed, while, on the other side, numerical simulations give a deeper insight into the e-fishbones dynamics. Linear and non-linear studies of e-fishbone instability have been performed for standard (peaked on-axis) [4] and inverted (peaked offaxis) suprathermal electron density profile, with moderately hollow q-profile. It is worth noting that the two situations are significantly different in terms of the characteristic resonance frequency as well as the fraction of suprathermal particles involved in the destabilization of the mode, confirming theoretical expectations. The study of e-fishbone nonlinear saturation mechanisms uses the test particle Hamiltonian method (TPHM) package [5], illuminating the complicate and unexplored dynamics of these modes. [1] K. Mcguire et al 1983 Phys. Rev. Lett [2] L. Chen,R.B. White and M.N. Rosenbluth, Phys. Rev. Lett (1984). [3] F. Zonca et al. Nuclear Fusion, 47 (2007) [4] G. Vlad et al. Nuclear Fusion, 53:083008, [5] S. Briguglio et al. Physics of Plasmas, 21:112301, This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect those of the European Commission. 78

79 P-30: linear benchmarks between hymagyc and hmgc codes G. Fogaccia, G. Vlad, S. Briguglio ENEA for EUROfusion, Via E. Fermi 45, Frascati, Italy Address of Submitting Author: The HYMAGYC code [1] is a HYbrid MAgnetohydrodynamics GYrokinetic Code suitable to study energetic particle (EP) driven Alfvénic modes in general high-pressure axisymmetric equilibria, with perturbed electromagnetic fields fully accounted for. HYMAGYC is composed by a MHD module interfaced with a particle-in-cell gyrokinetic (GK) solver. The MHD module solves resistive MHD linear equations taking into account the EP kinetic response through the divergence of the pressure tensor. The gyrokinetic module evolves particle flux coordinates in terms of gyrocenter equations of motion and yields the EP pressure tensor back to the MHD solver. The gyrokinetic ordering k ρ H 1 is assumed. A linear benchmark activity between HYMAGYC and HMGC [2] code is underway. The gyrocenter equations implemented in HYMAGYC have been reduced to the guiding-center description assumed in HMGC, and simulation parameters have been chosen to be consistent with the HMGC model validity limits; i.e., ρ H /a<<1, A =0, a/r 0 <<1 and circular magnetic flux surfaces. First, the GK solvers of HMGC and HYMAGYC have been tested with assigned perturbed electromagnetic fields, while the MHD modules of two codes have been checked assuming an "ad-hoc" driving term, treated explicitly. Then, benchmark between HYMAGYC and HMGC codes has been performed for two test cases, namely: (a) a/r 0 =0.1, circular shifted magnetic-surface equilibrium with parabolic safety factor radial profile (q 0 =1.1, q a =1.9) in presence of a isotropic Maxwellian initial energetic ion population, toroidal mode number n=2; (b) a/r 0 =0.1, circular shifted magnetic-surface equilibrium with parabolic safety factor radial profile (q 0 =1.71, q a =1.87), n=6 (the so-called ITPA Energetic Particle Group test case). Comparison of growth-rates of the most unstable modes vs. EP density, Larmor radius and thermal velocity between HYMAGYC and HMGC will be presented. [1] G. Vlad et al., 11th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (Kyiv 2009), paper P 25. [2] S. Briguglio, G. Vlad, F. Zonca, C. Kar, Hybrid magnetohydrodynamic gyrokinetic simulation of toroidal Alfvén modes Phys. Plasmas 2 (1995) pp This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme under grant agreement No The views and opinions expressed herein do not necessarily reflect those of the European Commission. 79

80 P-31: kinetic modelling of runaway electron dynamics A. Stahl 1, O. Embréus 1, E. Hirvijoki 1, G. Papp 2, M. Landreman 3, I. Pusztai 1 and T. Fülöp 1 1 Department of Applied Physics, Chalmers University of Technology, Göteborg, Sweden 2 Max Planck Institute for Plasma Physics, Garching, Germany 3 University of Maryland, College Park, MD, USA Address of Submitting Author: stahla@chalmers.se Abstract In the quest for avoidance or mitigation of the harmful effects of runaway electron formation [1], a greater understanding of the runaway electron phenomenon is required. Improved knowledge of runaway electron formation mechanisms, their dynamics and characteristics, as well as transport or loss processes that may contribute to runaway electron suppression, will benefit the fusion community and contribute to a safe and reliable operation of reactor-scale tokamaks. Kinetic simulation is the most accurate and useful method for investigating runaway electron dynamics, and we recently developed a new tool (called COllisional Distribution of Electrons (CODE) [2]) for fast and accurate study of these processes. Here, we discuss improvements to the model, which enable us to study the effect on the runaway electron distribution of important processes such as hot-tail runaway formation and synchrotron and Bremsstrahlung radiation emission. We also discuss an improved model for the knockon collisions leading to avalanche runaway electron generation. The above mentioned processes have important implications for the understanding of many phenomena, such as the effective critical electric field for runaway electron generation [3], and can even lead to the formation of non-monotonic features in the runaway electron tail [4]. Such features could drive kinetic instabilities, suppressing runaway growth. We will discuss the effects of hot-tail generation in connection with the improved avalanche source, which has the potential to alter the dynamics in the early stages of the runaway electron evolution. [ 1 ] E. M. Hollmann, et al., Phys. Plasmas 22, (2015). [ 2 ] M. Landreman, A. Stahl and T. Fülöp, Comp. Phys. Comm. 185, 847 (2014). [ 3 ] A. Stahl, E. Hirvijoki, J. Decker, O. Embréus and T. Fülöp, Phys. Rev. Lett. 114, (2015). [ 4 ] E. Hirvijoki, I. Pusztai, J. Decker, O. Embréus, A. Stahl and T. Fülöp, Radiation reaction induced nonmonotonic features in runaway electron distributions, to appear in J. Plasma Phys. 80

81 P-32: fast-ion d-alpha spectrum during east neutral- beam heated plasmas J. Huang 1, W.W. Heidbrink 2, M.G. von Hellermann 3, Y. Zhu 2, J. Chang 1, C. Wu 1, Y. Hou 4, W. Gao 1, Y.Yu 4 and EAST Team 1 1 Institute of Plasma Physics, Chinese Academy of Sciences, , Hefei, Anhui, China 2 University of California, Irvine, California 92697, USA 3 FOM Institute DIFFER, Nieuwegein 3430 BE, The Netherlands 4 School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui, ,China Address of Submitting Author: juan.huang@ipp.ac.cn Based on the charge exchange recombination between fast ions and a neutral beam, fast ion features can be inferred from the Doppler shifted spectrum of Balmer-alpha light from energetic hydrogenic atoms. With the upgrade of the Experimental Advanced Superconducting Tokamak (EAST) in 2015, both cocurrent and counter-current neutral beam injectors have been available, and each can deliver 2-4 MW beam power with kev beam energy. Based on the available probe beam, the fast ion D-alpha (FIDA) diagnostic system has been built [1] on EAST to investigate fast ion behavior. The system includes both tangential and vertical views to study the trapped and passing fast-ion velocity distribution and spatial profile. Beam modulation method is used here for background subtraction to get net FIDA signal. For the vertical view, the paired passive view is also available, allowing direct background subtraction. Since the FIDA diagnostic system was tested in the 2014 campaign, it has been updated to improve the reliability of the measurements, according to the mechanical problems. In the 2015 summer campaign, the validation of FIDA diagnostics is carried out under MHD-free neutral-beam heated plasmas, and the results for fast-ion D-alpha spectrum are compared with the simulated signals. References [1] J. Huang, et al., Rev. Sci. Instrum. 85, 11E407 (2014). This work was supported by National Magnetic Confinement Fusion Science Program of China under Contract No. 2011GB and 2015GB

82 P-33: evaluation of fluxes of lost alphas for gamma-ray diagnostics in iter V. Goloborodko 1,2, V. Kiptily 3, K. Schoepf 1, V. Yavorskij 1,2 1 Institute for Theoretical Physics, University of Innsbruck, Austria 2 Institute for Nuclear Research, Ukrainian Academy of Sciences, Kyiv, Ukraine 3 CCFE, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB, UK Address of Submitting Author:v.goloborodko@uibk.ac.at One of the possible diagnostics of energetic fusion alpha particle loss is gamma-ray diagnostics based on the measurements of gamma emission produced in nuclear reactions between escaped alphas and a beryllium target located near the ITER mid-plane [1]. The efficiency of such a diagnostic depends on the flux of alpha particles with energy E>1.7 MeV (threshold of the nuclear reaction with beryllium) at the target position. In ITER, due to the high plasma current, losses induced by collisional radial transport will exceed first orbit losses [2] and hence form a prominent contribution to the charged fusion product loss. Thus, in the case of low MHD activity, diffusive-convective collisional transport will be mainly responsible in ITER for the maximum heat loads and fluences caused by fusion alphas. The paper represents results of modelling of collisional fluxes of alphas escaping from ITER plasmas as well as their surface and velocity distributions on the plasma facing elements. The simulation is based on the new full gyro-orbit Monte-Carlo code DOLFI accounting for the effect of TF ripples and RMPs. A strong modulation of fusion alpha particle loss distributions over toroidal and poloidal coordinates is demonstrated. Calculations of alpha particle fluxes to the position of the beryllium target supposed for gamma-ray diagnostics in basic ITER scenarios will be presented. [1] V. Kiptily, On development of alpha-particle diagnostics in JET, 4 th Workshop FIMAD, Feb [2] V. Yavorskij, et al., JOFE (2015). DOI /s

83 P-34: interpretive and predictive modelling of fluxes of charged fusion products lost from tokamak plasmas V. Yavorskij 1,2, Yu. Baranov 3, V. Goloborod ko 1,2, D. Darrow 4, V.G. Kiptily 3, K. Schoepf 1, C. Perez von Thun 3 1 Institute for Theoretical Physics, University of Innsbruck, Austria (fusion@oeaw) 2 Institute for Nuclear Research, Ukrainian Academy of Sciences, Kyiv, Ukraine 3 CCFE, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB, UK 4 Princeton Plasma Physics Laboratory, New Jersey, Princeton, USA Address of Submitting Author: Victor.Yavorskij@uibk.ac.at In this study we assess the fluxes of charged fusion products (CFPs) lost from tokamak plasmas as a result of the radial transport associated with Coulomb collisions. In present day tokamaks with moderate or low plasma currents these fluxes result in heat loads and fluences onto the surface of plasma facing components, which can be comparable to or do even exceed those owing to the first orbit loss of CFPs [1-4]. In ITER-like tokamaks with high plasma currents and low MHD activity the collisional radial transport is expected to be accountable for the main contribution to CFP losses [5] and correspondingly responsible for the maximum heat loads and fluences caused by fusion alphas. The paper represents results of modelling of collisional fluxes of CFPs both from TFTR and JET plasmas with low and moderate plasma currents as well as of collisional fluxes of alphas escaping from ITER plasmas. Our simulation is based on the new full gyro-orbit Monte-Carlo code DOLFI accounting for the effect of TF ripples and RMPs. DOLFI delivers detailed distributions of diffusively-convectively lost fast ions over the coordinates of the plasma facing surface and over the velocity coordinates as well. A strong variation of CFP loss distributions over the toroidal and poloidal coordinates is demonstrated. The modelling results are in satisfactory agreement with measurements of velocity distributions of the loss additional to the first orbit loss of CFPs in TFTR (so-called delayed loss [1]) and in JET ( anomalous loss [4]). Results of predictive modelling of heat loads and fluences of fusion alphas for basic ITER scenarios will be presented. [1] S. Zweben, et al., Nucl. Fusion (2000). [2] K. Sugiyama, et al., J. Nucl. Mater., (2004). [3] V. Yavorskij, et al., Nucl. Fusion (2003). [4] Yu. Baranov, et al., EPS 2010, paper P [5] V. Yavorskij, et al., JOFE (2015). DOI /s

84 P-35: diagnosis of mirror trapped particles and excitation of energetic particle (ep) driven modes in lvpd A. K. Sanyasi, L. M. Awasthi, P. K. Srivastava, S. K. Mattoo and P. K. Kaw Institute for Plasma Research, Gandhinagar , India Address of Submitting Author: The LVPD plasma demonstrates nice exhibition of electron trapping in a belt region. This comes into existence only when EEF 1-3 is made active. The active EEF modifies the applied magnetic field of LVPD ( B 6.2G) by its strong perpendicular field of B 150G. Energetic z electrons are traced through peak floating potential measurements (mimics presence of energetic electrons) and approximately (5-10) % of bulk plasma electrons, which are energetic, are trapped in the region of plasma turbulence. In this paper, results demonstrating trapping of energetic electrons measured through various diagnostic techniques will be presented. The results from these diagnostics assume significance as they presents better representation of energetic electrons than what obtained through Electron Energy Distribution Function (EEDF), derived from I/V characteristics of Langmuir probe data. The EEDF does not offer clear distinction between for the plasma, when trapped electrons are present and absent in the region. Also, an effort is made to correlate these electrons with the excited plasma turbulence. The (, k) spectrum of the turbulence in the region suggest that long and short wave length modes x exist along and across B with their respective wave numbers as, k / k Comparison z of diagnostics outcome and mode identification of observed, low frequency ( ~ LH ce ) EP driven turbulence, its correlation with the instabilities excited in magnetosphere and tokamaks will be presented in the conference. References 1. S. K. Singh, P. K. Srivastava, L. M. Awasthi, et. al. Rev. Sci. Instrum., 85, (2014). 2. S. K. Mattoo, S. K. Singh, L. M. Awasthi, et. al. Phys. Rev. Lett. 108, (2012). 3. A. K. Sanyasi, L. M. Awasthi, S. K. Mattoo, et. al. Phys. Plasmas, 20, (2013). 84

85 P-36: diagnosing mev range deuterons with neutron and gamma ray spectroscopy at jet M. Nocente 1,2, J. Eriksson 3, F. Binda 3, C. Cazzaniga 2,4, S. Conroy 3, G. Ericsson 3, L. Giacomelli 2, G. Gorini 1,2, C. Hellesen 3, A. Hjalmarsson 3, A. S. Jacobsen 5, V. Kiptily 6, M. Mantsinen 7,8, M. Salewski 5, M. Schneider 9, S. Sharapov 6, M. Skiba 3, M. Tardocchi 1,2, M. Weiszflog 3 and JET Contributors EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK 1 Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano-Bicocca, Milano, Italy 2 Istituto di Fisica del Plasma Piero Caldirola, Associazione EURATOM-ENEA-CNR, Milano, Italy 3 Department of Physics and Astronomy, Uppsala University, Sweden 4 ISIS Facility, Rutherford Appleton Laboratory, Science Didcot, UK 5 Technical University of Denmark, Department of Physics, DK-2800 Kgs. Lyngby,Denmark 6 CCFE, Culham Science Centre, Abingdon, UK 7 Catalan Institution for Research and Advanced Studies, Barcelona, Spain; 8 Barcelona Supercomputer Center, Barcelona, Spain 9 CEA, IRFM, F Saint-Paul-lez-Durance, France A particularly effective heating scheme to accelerate ions to the MeV energy range at JET is to couple ion cyclotron radio frequency (ICRF) heating at the third harmonic into an injected deuteron beam in a deuterium plasma. This heating mechanism was the basis for a dedicated experiment in the latest JET campaign [1,2] and is of special interest for diagnostic applications, as it allows testing the capability of the present systems to diagnose the fast ion energy distribution in preparation of the forthcoming deuterium-tritium campaign. In this work we present the experimental observations made in the latest JET third harmonic acceleration experiment (summer 2014) by means of an extended set of neutron and gamma-ray spectrometers observing the plasma along a vertical and an oblique line of sight. Data from the whole set of detectors (which include high resolution gamma-ray spectrometers, a time of flight neutron spectrometer, a neutron camera as well as a scintillator and diamond neutron detectors, operated simultaneously for the first time) are used to determine parameters of the fast ion energy distribution. We also discuss the sensitivity of the different diagnostics in fast ion phase space and relate it to the measurements. A one dimensional, extended Stix model of the deuteron velocity distribution is used first to extract the energy cut-off in the deuteron phase space and the ICRF coupling constant from neutron and gamma-ray data. It is found that, while detectors sharing the same line of sight provide consistent results within error bars, the parameters derived from measurements along different lines of sight do not appear to agree. In particular, as also revealed by velocity space weight function calculations of neutron and gamma-ray spectroscopy, oblique measurements show a certain sensitivity to the spatial distribution and pitch angle structure of the energetic ions around the ICRF resonance, which is not correctly portrayed by the adopted one dimensional model. A more detailed framework based on first principle distribution functions calculated by the PION and SPOT/RFOF codes is finally used to improve our description of neutron and gamma-ray emission during the experiment and compared to data for both lines of sight. [1] S. Sharapov et al. "Fast Ion D-D and D- 3 He Fusion on JET", this meeting: [2] M. Schneider et al. "Modelling 3 rd harmonic Ion Cyclotron acceleration of D beam for JET Fusion Product Studies experiments", this meeting 85

86 P-37: a comparison of reconstruction methods for inferring the fast-ion distribution function from multiple fida measurements L. Stagner and W.W. Heidbrink University of California, Irvine, California 92697, USA A.S. Jacobsen and M. Salewski Technical University of Denmark, Department of Physics, DK-2800 Kgs. Lyngby, Denmark B. Geiger, M. Weiland, and the ASDEX Upgrade team Max-Planck-Institute for Plasma Physics, Boltzmannstr. 2, Garching, Germany The Fast-ion D α (FIDA) diagnostic measures light that energetic particles emit in fusion plasmas. The diagnostic is sensitive to different velocity space regions depending on the viewing angle relative to the magnetic field.[2] Consequently, viewing chords that share a radial location give different, yet still valid, results. Velocity space tomography allows us to combine the rich information contained in FIDA spectra from these viewing chords to infer the complete local fast-ion distribution function from the different partial views[1]. Tomography involves solving a system of linear equations which are often illconditioned and consequently sensitive to measurement error. There are a number of ways to regularize these types of systems to make them amenable to physical solutions. These methods include Truncated Singular Value Decomposition (TSVD), Zeroth and First Order Tikhonov Regularization, the Maximum Entropy Method, and Minimum Fisher Information Regularization. The best regularization method is often application dependent. In this work we present a survey of the different regularization methods using realistic synthetic data to determine the most effective regularization method for velocity space tomography. Preliminary results show, for realistic distributions, that Minimum Fisher Information Regularization produces the best results. We also demonstrate the application of the described methods to real data to study the redistribution of fast-ions during a sawtooth crash at ASDEX Upgrade. An extension of velocity space tomography to allow for the inference of the full fast-ion distribution in constants of motion space will also be presented. 1] M. Salewski, B. Geiger, A. S. Jacobsen, M. García-Muňoz, W. W. Heidbrink, S. B. Korsholm, F. Leipold, J. Madsen, D. Moseev, S. K. Nielsen, et al. Measurement of a 2d fast-ion velocity distribution function by tomographic inversion of fast-ion d-alpha spectra. Nuclear Fusion, 54(2):023005, [2] M. Salewski, B. Geiger, D. Moseev, W. W. Heidbrink, A. S. Jacobsen, S. B. Korsholm, F.Leipold, J. Madsen, S. K. Nielsen, J. Rasmussen, et al. On velocity-space sensitivity of fast-ion d-alpha spectroscopy. Plasma Physics and controlled Fusion, 56(10):105005,

87 P-38: preliminary results of the east integrated energetic neutral particle analyzer and its conceptual design on the hl-2a/m tokamaks Y.B. Zhu 1, J.Z. Zhang 2, G.Q. Zhong 2, L.M. Yu 3, J. Lu 3, W.W. Heidbrink 1, B.N. Wan 2, J.G. Li 2, Y. Liu 3, X.T. Ding 3, and X.R. Duan 3 1 Department of Physics and Astronomy, University of California, Irvine, California , USA 2 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei , China 3 Southwestern Institute of Physics, Chengdu , China Address of Submitting Author: y.zhu@uci.edu A package of full function integrated, compact silicon photodiode based solid state neutral particle analyzers (ssnpa) has been successfully developed, implemented and commissioned for energetic particle (EP) relevant studies on the Experimental Advanced Superconducting Tokamak (EAST) [1,2]. The system consists of 7+9 individual channels on two long vertical up-ports and arrays mounted on a retractable feedthrough on a horizontal port. The system functionality has been proved by the preliminary data obtained from the EAST 2014 and 2015 summer campaigns. Significant signal enhancements from both ion cyclotron resonant heating (ICRH) and neutral beam injection (NBI) are observed, with no clear direct response to either lower hybrid wave (LHW) or electron cyclotron resonant heating (ECRH) under similar plasma conditions. ssnpa data is consistent with neutron flux detected by traditional counters and a set of new scintillators. Significant EP related engineering upgrades and experimental plans have been setup on the HL-2A and its successor HL-2M tokamak [3], as well as on the EAST. Compared to the complicated EAST engineering and operational realities, the Chengdu tokamaks provide ssnpa diagnostics with better accessibility and much simpler in-vacuum environment. Aiming at simultaneous measurements with fast temporal, fine spatial and coarse energy resolutions, the HL-2A/M ssnpa conceptual design and engineering optimization details will be presented. References [1] Y.B. Zhu et al., Development of an integrated energetic neutral particle measurement system on experimental advanced full superconducting tokamak, Rev. Sci. Instrum. 85, 11E107 (2014). [2] Y.B. Zhu et al., Compact solid-state neutral particle analyzer in current mode, Rev. Sci. Instrum. 83, 10D304 (2012). [3] Q.W. Yang et al., Diagnostics for energetic particle studies on the HL-2A tokamak, Rev. Sci. Instrum. 85, 11D857 (2014). [4] J. Y. Cao et al., Conceptual design of 5MW-NBI injector for HL-2M tokamak, Fus. Eng. Des. 88, (6-8) (2013). 87

88 P-39: fast ion d-d and d- 3 he fusion on jet S.E.Sharapov, T.Hellsten 1, V.G.Kiptily, T.Craciunescu 2, J.Eriksson 3, M.Fitzgerald, J.-B.Girardo 4, V.Goloborod ko 5,6, A.Hjalmarsson 3, A.S.Jacobsen 7, T.Johnson 1, Y.Kazakov 8, T.Koskela 9, M.Mantsinen 10, I.Monakhov, F.Nabais 11, M.Nocente 12, C. Perez von Thun 5, F.Rimini, M.Salewski 7, M.Santala 9, M.Schneider 4, M.Tardocchi 12, M.Tsalas, V.Yavorskij 5,6, V.Zoita 2 and JET Contributors*. CCFE, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB, UK 1 KTH Royal Institute of Technology, SE , Stockholm, Sweden 2 National Institute for Laser, Plasma and Radiation Physics, Bucharest, Romania 3 Dept. of Physics and Astronomy, Uppsala University, Uppsala, Sweden 4 CEA, Cadarache, France 5 Institite for Theoretical Physics, University of Innsbruck, Austria 6 Institute for Nuclear Research, Ukraininan Academy of Sciences, Kiev, Ukraine 7 Technical University of Denmark, Department of Physics,DK-2800 Kgs. Lyngby, Denmark 8 LPP-ERM/KMS, TEC Partner, Brussels, Belgium 9 Aalto University, PO Box 14100, FIN-00076, Aalto, Finland 10 ICREA-Barcelona Supercomputer Center, Barcelona, Spain 11 IST, Centro de Fusao Nuclear, Lisbon, Portugal 12 CNR-IFP and University di Milano-Bicocca, Milan, Italy *See Appendix of F. Romanelli et al., Proc. 25th IAEA FEC 2014, Saint Petersburg, Russia Third harmonic ICRH [1,2] has been shown at JET to be an effective tool for accelerating NBI-produced beam ions to the MeV energy range, suitable for studying ITER relevant fast particle physics, as well as for preparing JET fusion product diagnostics for a future D-T campaign. By adding 3 MW of ICRH power at 3rd harmonic to 3-4 MW of D NBI in D plasma, it was possible in recent experiments to increase the yield of D-D neutrons by an order of magnitude, up to n/s. Neutron emission spectra measured in these experiments, both by time-of-flight analysis and using a novel diamond detector, reveal broad spectra with neutron energies up to ~6 MeV for D-D neutrons [3]. This broadening of the D-D neutron spectra results from ICRH acceleration of NBI-produced D with starting energy ~100 kev into the MeV energy range. Control of the D-D neutron energy spectrum was demonstrated by varying plasma density, ICRH power, and pitch-angle of NBI, which play a key role for the coupling between the beam and ICRH. The experiment was extended to ICRH acceleration of D beams in D- 3 He plasmas with amounts of 3 He increasing discharge-bydischarge up to D: 3 He 70:30. The aneutronic D- 3 He fusion, giving birth to 15 MeV protons and 3.7 MeV alpha-particles has been studied on JET before [4]. In contrast to 3He minority ICRH [5] and 3He NBI [6], the ICRH acceleration of D beam in D-3He plasma generates a fast Distribution function with a cut-off in energy, which is easy to control. The rate of D- 3 He fusion was measured from 17 MeV γ-rays produced by D( 3 He, γ) 5 Li reaction and found to be ~10 kw. High resolution γ-spectrometry, NPA, scintillator probe, and Faraday cups were all employed for measuring ICRH-accelerated D ions and charged fusion products of both D- 3 He and D-D reactions. Analysis of the experiments with the suite of ICRH-modelling tools PION, SELFO, and SPOT/RFOF is found to agree with the measured neutron and γ-ray spectra and profiles [7,8]. Remarkably long sawtooth-free periods of up to ~2.5 s were obtained in these plasmas and Alfven Eigenmodes were excited. These results pave the way for further experiments such as counteracting the effective, but ultimately undesirable sawtooth stabilisation by fast ions observed in the experiment using a separate ICRH source, as well as for investigating fast ion effects on AEs and other plasma instabilities. This work has received funding from Euratom and the RCUK Energy Programme [grant number EP/I501045]. The views and opinions expressed herein do not necessarily reflect those of the European Commission. [1] L. G.Eriksson et al., Nucl. Fusion (1998); [2] M.Mantsinen et al., Phys. Rev. Lett. 88, (2002); [3] M.Nocente, this Conference; [4] P.E.Stott, Plasma Phys. Control. Fusion 47, 1305 (2005); [5] J.Jacquinot, G.Sadler, Fusion Technology 21, 2254 (1992); [6] F.B.Marcus et al., Plasma Phys. Control. Fusion 34, 1371 (1992); [7] M.Schneider, this Conference ; [8] M.Mantsinen, this Conference. 88

89 P-40: measurement of phase space structure of fast ions interacting with Alfvén eigenmodes K. Nagaoka 1,2,3, M. Osakabe 1,2, M. Isobe 1,2, K. Ogawa 1,2, Y. Suzuki 1,2, S. Kobayashi 3, S. Yamamoto 3, Y. Miyoshi 4, Y. Katoh 5, J.M. Fontdecaba 6 1 National Institute for Fusion Science, Toki, , Japan 2 The Graduate University for Advanced Studies, Hayama, , Japan 3 Institute of Advanced Energy, Kyoto University, Uji, , Japan 4 Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, , Japan 5 Graduate School of Science, Tohoku University, Sendai, , Japan 6 Laboratorio Nacional de Fusión CIEMAT, Madrid, Spain Address of Submitting Author: nagaoka@nifs.ac.jp Experimentally observed Alfven eigenmodes (AEs) show nonlinear behaviors such as intermittency, fast sweep in frequency and so on. In order to understand such nonlinear behaviors of AEs, it is widely recognized that the phase space dynamics have to be taken into account. However, there are few direct measurements of phase space structure in experiments so far. Here, we propose to apply the waveparticle interaction analyzer (WPIA) technique being developed for magnetosphere plasma physics (ERG project) to magnetically confinement fusion experiments. The concept of WPIA is a phase detection between particle flux and the wave for the quantitative evaluation of energy transfer between them. We have developed a high speed pulse analyzer system for WPIA using the field programmable gate array (FPGA) module, and installed the system to the large helical device (LHD). One channel of Mirnov signal and eight channels of semi-conductor fast neutral analyzer (Si-FNA) signals are digitized with sampling rate of 50MS/s (maximum), which is significantly higher (factor of 104) than that of conventional pulse height analyzer technique and enable us to evaluate the phase with respect to the wave. The particle detection time and particle energy are recorded for all particles detected by the Si-FNAs. The detail of the system and some phase space structures observed in LHD experiments will be discussed in the meeting.). Fig. 1 Conceptual drawing of wave-particle interaction analyzer (WPIA 89