Overview of Experimental Results on HL-2A

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1 1 SWIP Overview of Experimental Results on X.R. Duan on behalf of team Southwestern Institute of Physics, Chengdu, China In collaboration with University of Science and Technology of China, Hefei, China ASIPP, Hefei, China CEA\IRFM, Cadarache, France FOM Institute for Plasma Physics Rijnhuizen, The Netherlands NIFS, Toki, Japan Kyoto University, Kyoto, Japan Acknowledgements MPI für Plasmaphysik, IPP-Juelich, Germany GA, PPPL, LLNL, UCI, UCLA, UCSD, USA JAEA, Japan ENEA, Frascati, Italy Kurchatov Institute, Russia HUST, IOP, Tsinghua University, China

2 tokamak-present status R: 1.65 m a:.4 m Bt: 1.~.7 T Configuration: Limiter, LSN divertor Ip: 15 ~ 45 ka ne: 1. ~ 6. x 119 m-3 Te: Ti: 1.5 ~ 5. kev.5 ~ 1.5 kev Auxiliary heating: ECRH/ECCD: MW (4/68 GHz/5 kw/1 s) modulation: 1~3 Hz; 1~1 % NBI(tangential): 1.5 MW LHCD: 1 MW (/.45 GHz/5 kw/1 s) Fueling system (H/D): Gas puffing (LFS, HFS, divertor) Pellet injection (LFS, HFS) SMBI (LFS, HFS) LFS: f =1~6 Hz, pulse duration >.5 ms gas pressure < 3 MPa nd IAEA Fusion Energy Conference, October 8, Geneva

3 3 Outline of the talk Transport study Spontaneous particle transport barrier Non-local transport triggered by SMBI Zonal flow & turbulence Low frequency zonal flow GAM density fluctuation Two regime fluctuations φ ~ f φ ~ ne ~ f Diagnostics with high resolution : MW Reflectometry (1ms/ ~1.5cm) ECE (16 CHs/ 5µs) Soft x ray arrays (5 1 CHs/ 5 µs) HCN Interferometer (8 CHs/ 1 µs) MW Doppler Reflectometer Perturbation Source : Pulsed SMBI Modulated ECRH MHD activities under ECRH Summary & outlook ~ 3D GAM ( φ ), K.J.Zhao PRL 6 f

4 4 Spontaneous particle transport barrier n e ( m - 3 ) L n ( c m ) r ( c m ) reproducible if ne > nc #7557 pitb pitb 5 m s 4 m s 4 8 m s 5 m s After SMBI r ( c m ) barrier is well-like critical density: W.W.Xiao (EX/P5-4) Wed. PM n ~. 1 m related to steepness of density ne/negradient: I p ( k A ) H a ( a. u. ) r ( c m ) V e l o c i t y ( k m / s ) V*e: electron diamagnetic drift velocity ( a ) ( b ) ( c ) p I T BpITB MHD without obvious change -D density gradient After SMBI pulse t ( m s ) turbulent poloidal rotation velocity n e ~. 8 n e ~. 6 n e ~ 1. 9 n e ~ r ( c m ) V e * M H D ( a. u. ) n e ( m - 3 ) 6 4

5 5 Density Modulation Analysis for pitb n H a ( a. u. ) S M B I ( a. u. ) P h a s e ( r a d ) A m p l i t u d e e modulation by SMBI frequency: 9.6 Hz pulse duration: 6 ms gas pressure: 1.3 MPa t ( m s ) #7593 ( a ) ( b ) S i m u. E x p. S o u r c e d e p o s i t i o n S i m u. E x p. r ~ 5.4 cm r a d i u s ( c m ) n e t Analytical model [S.P.Eury Phys.Plasma 5] 1 = r n rd e + r r f=9.6 Hz, rdep=5.4 cm rvn e + S( r, t) Domain 1: D1=.1 m/s, V1=1.m/s Domain : D=.6m/s, V =-.7m/s Domain 3: D3=.5 m/s, V3=6.m/s D ( m / s ) r ( c m ) V remains negative inside barrier D is rather well-like than step-like The density threshold may be correlated to the TEM/ITG transition via the collisionality. pitb may be created initially by the discontinuity or jump in the convective velocity during the TEM/ITG transition, or by two convective velocities in opposite direction (inward/ outward) at the barrier D 1 3 W.W.Xiao (EX/P5-4) Wed. PM V V ( m / s )

Non-local transport triggered by SMBI #6351 Under some discharge

5 due to cooling, but Te increases in the core #8363 core r ne = 1.

6 Non-local transport triggered by SMBI #6351 Under some discharge conditions after SMBI the Te decreases at r/a >.5 due to cooling, but Te increases in the core #8363 core r ne = 1.36 non-local effect depends on: electron density heating power gas pressure of SMB penetration depth Bt =.36 T, Ip = 3 ka, PECRH = 8 kw H.J.Sun (EX/P5-3) Wed. PM nd IAEA Fusion Energy Conference, October 8, Geneva 6

7 7 Non-local transport triggered by SMBI Characteristics of non-local effect : The core Te rise up to 5%. H.J.Sun (EX/P5-3) Wed. PM Both the thermal radiation and the Ha emission decrease, accompanying with the increase of the stored energy The duration of the process could be prolonged by changing the gap between SMB pulses #8364 FFT of Te perturbation by modulated SMBI A m p l i t u d e ( a. u. ) s t n d 3 t h P h a s e ( d e g ) s t n d 3 n d r ( c m ) r ( c m ) ms 4ms 4ms 14ms a clear phase jump at the reverse position, two peaks in the amplitude may indicate two perturbation sources in the regions outside and inside the inversion radius.

8 8 Outline of the talk Transport study Spontaneous particle transport barrier Non-local transport triggered by SMBI Zonal flow & turbulence Low frequency zonal flow GAM density fluctuation Two regime fluctuations MHD activities under ECRH Summary & outlook φ ~ f φ ~ ne ~ f ~ 3D GAM ( φ ), K.J.Zhao PRL 6 f

9 9 Low Frequency Zonal Flow four probe arrays: A, B, C, D coherent mode at ~8.5 khz GAMZF similar to [K.J. Zhao PRL 6] [T.Lan PPCF 8] frequency resolution A, C B, D 1, k θ k ϕ k r LFZF poloidally & toroidally symmetric mode m= / n= consistent with theory prediction and simulation for LFZF [T.S.Hahm PPCF ] f : < 3kHz A.D.Liu (EX/P5-3) Wed. PM Mode Number Corr. Coeff.

10 1 Radial spectral characterization of LFZF ( r f ) s k S k = k r ( r, f ) S ( k, f ) r ρ i =. 6cm local wavenumber-frequency spectrum By measuring the cross correlation between probes (the radial separation from to 9mm), the correlation length of the LFZF is obtained: L LFZF r 6 mm ± mm GAMZF propagates radially outwards LFZF propagates radially with a small net outward averaged wavenumber: k LFZF r ρ =.33 ~ o(.1) k i wavenumber width: LFZF r i GAM r k ρ =.19 ~ o(1) k ρ i GAM r A.D.Liu (EX/P5-3) Wed. PM ρ i

11 GAM density fluctuation A P S ( a. u. ) A P S ( a. u. ). 4...1 GAM I s V f (a) f GAM =9.8kHz Coherency 4 6 8 f(khz) Is: saturation ion current Vf: floating potential (b) θ(/π rad).9.6.3 1 I s,v f noise level -1 4 6 8 f(khz) L.

11 11 GAM density fluctuation A P S ( a. u. ) A P S ( a. u. ) GAM I s V f (a) f GAM =9.8kHz Coherency f(khz) Is: saturation ion current Vf: floating potential (b) θ(/π rad) I s,v f noise level f(khz) L.W.Yan (EX/P5-33) Wed. PM (c) (d) n S(m, n, f GAM ) f GAM =9.8 khz m mainly localize at m < 1. and n =.5 ±.15 rake and 3-step LP arrays 1.33 m The peak at frequency fgam = 9.8 khz not only in Is, but also in Vf, Theoretical frequency is 9. khz with fgam~(te/ Mi).5/ (πr) [P.H.Diamond PPCF 5] FWHM of the GAM density fluctuation ~4 khz lifetime 5 µs. The phase shift between Is and Vf is ~.45π, consistent with the theoretical prediction (.5π )

12 GAM density fluctuation squared auto-bicoherence summed bicoherence L.W.Yan (EX/P5-33) Wed. PM The significant coupling regions: f GAM =f 1 +f =9.8 khz, <f <8 khz The generation of GAM density fluctuation is plausibly generated by the small scale ambient turbulence through nonlinear three wave couplings (reverse cascade) nd IAEA Fusion Energy Conference, October 8, Geneva 1

Two regime fluctuations The distinct dispersion relation for the low frequency fluctuation (LFF) and high frequency ambient turbulence (HFAT) FWHM of -4kHz the lifetime of the LFF ( -1kHz) ~5-5µs The

13 Two regime fluctuations The distinct dispersion relation for the low frequency fluctuation (LFF) and high frequency ambient turbulence (HFAT) FWHM of -4kHz the lifetime of the LFF ( -1kHz) ~5-5µs The poloidal and radial wave vectors.9cm and 1.9cm Correlation length: poloidal ~6.5 cm, toroidal ~ 8 cm -1-1 respectively K.J.Zhao (EX/P5-34) Wed. PM Autocorrelation time of HFAT ~5µs, poloidal correlation length ~.5 cm nd IAEA Fusion Energy Conference, October 8, Geneva [K.J. Zhao, PRL 6, Phys.Plasmas 7] 13

5 113cm- 3 ˆ ( f = f ) ( ) /[ ( ) ( ) ( 1 + f = B f < φ f1 φ f > < φ f = f1 + f b bispectrum analysis Β ( f ) = < φ ( f 1) φ ( f ) φ (

14 14 Two regime fluctuations The phenomena is reproducible for various discharge conditions Nonlinear Coupling A. Bt=.4T, Ip=3kA, ne=.5 113cm-3, B. Bt=.T, Ip=kA, ne=1 113cm-3, C. Bt=1.4T, Ip=18kA, ne=.5 113cm- 3 ˆ ( f = f ) ( ) /[ ( ) ( ) ( 1 + f = B f < φ f1 φ f > < φ f = f1 + f b bispectrum analysis Β ( f ) = < φ ( f 1) φ ( f ) φ ( f = f1 + f ) The squared auto-bicoherence about f = f1± f = -4kHz, is higher than the rest, indicating that the LFF is possibly generated by nonlinear three wave coupling ) > ] K.J.Zhao (EX/P5-34) Wed. PM

15 15 Outline of the talk Transport study Spontaneous particle transport barrier Non-local transport triggered by SMBI Zonal flow & turbulence Low frequency zonal flow GAM density fluctuation Two regime fluctuations MHD activities under ECRH Summary & outlook

16 16 e-fishbone Instability The e-fishbone excited by ECRH deposited at both HFS and LFS. W.Chen (EX/P8-11) Fri. AM The mode occurs along with the increase of the 35-7 kev energetic electrons, which dominate the effect.. 8 I s x E C R H I s x H X p h o t o n n u m b e r D C A B w i t h f i s h b o n e k e V A : m s B : C : D : t i m e ( m s ) E n e r g y ( k e V )

e-fishbone Instability W.Chen (EX/P8-11) Fri. AM (arb.units).8 I sx.6.4.

17 e-fishbone Instability W.Chen (EX/P8-11) Fri. AM (arb.units).8 I sx time (ms) f (khz) The poloidal rotation of m = 1 modes is in the electron diamagnetic drift direction time (ms) The frequency is between 3 and 7 khz. nd IAEA Fusion Energy Conference, October 8, Geneva 17

18 Suppression of tearing mode with ECRH The suppression

increased subsequently. Z(m) -.85 1.5 1.7 R(m).

5 4 4 44 46 3 1 4 4 44 46 t (ms) 3 1 The effect can be

18 18 Suppression of tearing mode with ECRH The suppression of m=/n=1 tearing mode has been realized with off-axis heating located around q= surface..85 ECRH The m= activity does not resume even after the ECRH is turned off. After ECRH switch-off central SXR intensity can be increased subsequently. Z(m) R(m).35 ECRH(kW) dbθ/dt (a.u.) f (khz) 1.5. ECRH t (ms) 3 1 The effect can be additive by applying successive ECRH pulses. MHD-free phase and a continuous confinement improvement have been achieved. Yi Liu (EX/P9-) Fri. PM

19 19 Outline of the talk Transport study Spontaneous particle transport barrier Non-local transport triggered by SMBI Zonal flow & turbulence Low frequency zonal flow GAM density fluctuation Two regime fluctuations MHD activities under ECRH Summary & outlook

20 Summary and Outlook Since last FEC, heating systems of MW ECRH/ECCD, 1.5 MW NBI; diagnostics such as high resolution ECE, multichannel Thomson scattering system and HCN laser interferometer, etc. have been developed and installed. Progresses have been achieved on studying and understanding the physics of transport, turbulence and zonal flows, MHD instabilities and energetic electron dynamics. The short term physics program: MHD activities, including energetic particle effect, mode control; RF heating and current drive, including mechanism, efficiency and control; H-mode physics, including formation mechanism or trigger, pedestal characteristics and edge localized modes; Particle, momentum and energy transports and confinements: including micro-instabilities, turbulence and zonal flows, ITB formation mechanism, the role of magnetic and flow shears; SOL and divertor physics, including blob, turbulence and transport in SOL, particle and heat loading on the plasma facing components.

21 1 Contributions to this conference Dong, Y.B. EX/P3-8 Tue. PM Sun, H.J. EX/P5-3 Wed. PM Ding, X.T. EX/P5-4 Wed. PM Liu, A.D. EX/P5-3 Wed. PM Yan, L.W. EX/P5-33 Wed. PM Zhao, K.J. EX/P5-34 Wed. PM Chen, Wei EX/P8-11 Fri. AM Liu, Yi EX/P9- Fri. PM

22 A method for particle transport by means of SMBI Evolution of the density profile measured by scanning microwave reflectometer during pulsed SMBI Amplitude and phase from FFT of the density perturbation signals modulated by pulsed SMBI Diffusivity profile calculated from the phase SMBI system and H alpha measurement gradient second harmonic, third harmonic nd IAEA Fusion Energy Conference, October 8, Geneva

23 3 Comparing Particle Transport with different density s h o t # , 1 s t h a r m o n i c A Phase a m p l i t u d e p h a s e r / c m s h o t # ( a ) ne n e / c m m s 7 3 m s ( b ) r a d i u s / c m

24 High density experiment ne = m Shot 7498 SMBI: delay m, 5 pulses, pulse width 3 ms, interval 1ms, gas(d ) pressure.6mpa. The LHS SMBI system is easily controllable. As a fuelling method,smbi may substitute for gas puffing. nd IAEA Fusion Energy Conference, October 8, Geneva 4

25 5 Radial correlation of LFZF For probes B and D are radially moveable, the radial correlation length of the LFZF could be estimated; By measuring the cross correlation between tip 1 and (the radial separation from to 9mm), the correlation length of the LFZF is obtained : L LFZF r 6 mm ± mm A.D.Liu (EX/P5-3) Wed. PM

SUMMARY OF EXPERIMENTAL CORE TURBULENCE CHARACTERISTICS IN OH AND ECRH T-10 TOKAMAK PLASMAS

SUMMARY OF EXPERIMENTAL CORE TURBULENCE CHARACTERISTICS IN OH AND ECRH T-1 TOKAMAK PLASMAS V. Vershkov, L.G. Eliseev, S.A. Grashin. A.V. Melnikov, D.A. Shelukhin, S.V. Soldatov, A.O. Urazbaev and T-1 team