Association Euratom Tekes

Transcription

1 ITER Test Blanket Module Experiment (TBM) on DIII-D Tokamak in San Diego T. Tala 1 and the TBM International Team and DIII-D Team 1 VTT, P.O Box 1000, FI VTT

2 2 The TBM Experiment International Team Comprised All the 7 ITER Parties Joseph Snipes ITER Naouki Oyama Japan Kouji Shinohara Japan Hogan Jhang S Korea Kwang-Il You S Korea Xiang Gao China Songlin Liu China Yanjing Chen China Guoyao Zheng China Gabriella Saibene Europe Antti Salmi Europe Tuomas Tala Europe Peter de Vries Europe Vladimir Pustovitov Russia N Submarian India Don Spong USA David Gates USA Jong-Kyu Park USA

3 Introduction 3 ITER TBM experiments performed on DIII-D from November 11-20, experimental days (8:00-20:00 tokamak operation) 254 plasma shots (over 90% useful plasma discharges) Experiments planned and performed by the International TBM team comprised of scientists from the 7 ITER partners and the ITER organization with on-site and remote participation. Unique tokamak physics experiment triggered by the ITER team and including all ITER parties. Main experimental objectives: Determine the effects of the TBM mock-up on various plasma properties to be able to extapolate to ITER H-mode threshold and performance (confinement, pedestal, Edge Localised Modes ELMs, rotation, etc.) ELM suppression by resonant magnetic perturbations Locked modes and TBM error field correction Fast ion transport

4 TBM Mock-up on DIII-D Tokamak 4 Racetrack coils B φ (toroidal magnetisation) Vertical solenoid B θ (poloidal magnetisation) TBM coil assembly fits into available DIII-D port Courtesy of M. Schaffer Matches ITER TBM far magnetic field Too narrow to match near field in detail Moveable, R 1.0 ITER meter To model TBM recession Mockup capable of ~3x ITER B/B 0 To match surface-average amplitude of 6 ITER TBMs Cannot match ITER s 6-TBM spectrum Mock-up was set to various distances from plasma Recession TBM mock-up removed after the experiments and can be put back if needed

5 5 DIII-D TBM Mock-up Field Narrower than the ITER One ITER TBM Field at ITER plasma surface 800 DIII D Mockup Field at DIII-D plasma surface 400 B TOR, B R, B Z 200 gauss gauss B TOR, B R, B Z Z (m) Z (m) Note that DIII-D and ITER have different magnetic handedness

6 6 Main results from the DIII-D TBM experiments

7 TBM Does Not Affect the H-mode Power Threshold Very important and positive result for ITER! 7 L-mode H-mode L-mode H-mode

8 8 The Effect of TBM Modest on Density and Pressure TBM causes a reduction of around 10% in density and pressure (betan) and consequently energy at the expected ITER TBM perturbation field ~10% ~10% ~10% ~10% Time (ms)

9 9 The Largest Effect of TBM Is Observed on Plasma Rotation Plasma rotation drops after TBM switch on, reduction up 80% Toroidal rotation profile rotation confinement Rotation pressure

10 The TBM Has No Discernible Impact on ELM (Edge Localised Mode) Suppression by Resonant Magnetic Perturbations (Planned Also in ITER) 10 ELM suppression coil Signature of ELMs

11 Reduction in the Density, Beta, Confinement Factor and Plasma Rotation with Increasing TBM Current (Local Ripple) 11 (Local ripple caused by TBM in brackets, %) Density reduction Confinement reduction Pressure reduction Rotation reduction

12 The Effects of the TBM Are Decreased by Recessing the TBM Further from the Plasma 12 Relative changes in density, pressure, confinement and rotation all decrease with recessed distance still ~5% at furthest distance Recessing TBM by 15 cm decreases the effects of TBM by 3 4 times (local ripple in brackets, %) Density reduction Confinement reduction Pressure reduction Rotation reduction

13 13 Conclusions TBM experiments carried out successfully by the International Team comprising of all 7 ITER parties, including very strong participation by Tekes These results provide a robust base for the final ITER TBM design (discussed widely in the TBM workshop organised in ITER in April 2010) The TBM ripple has no significant effect on the H-mode power threshold The TBM ripple affects the confinement properties of H-mode plasmas most significant effect is observed on plasma toroidal rotation with decreases of up to 80% confinement times, beta and density (plasma performance) exhibit smaller reduction of 5-15% Rotation reduction appears to be characteristic of a non-resonant braking torque The TBM ripple has no significant effect on the ability to suppress ELMs by resonant magnetic perturbation No convincing indications of increased global fast ion loss fraction due to TBM consistent with numerical modelling (ASCOT modelling on-going here by Tekes )