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22-27 October 2018
Mahatma Mandir Conference Centre
Asia/Kolkata timezone
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Simulations of energetic particle driven instabilities and fast particle redistribution in EAST tokamak

23 Oct 2018, 11:05
20m
Mahatma Mandir Conference Centre

Mahatma Mandir Conference Centre

Gandhinagar (nearest Airport: Ahmedabad), India
Oral THW - Magnetic Confinement Theory and Modelling: Wave–plasma interactions; current drive; heating; energetic particles EX/1-TH/1 Energetic Particles

Speaker

Dr Wei Shen (Institute of Plasma Physics, Chinese Academy of Sciences)

Description

Instabilities driven by energetic particles including fishbones and Alfven eigenmodes, together with fast particle loss and redistribution due to resonant magnetic perturbations (RMPs), have been investigated numerically with codes M3D-K, MEGA, and GYCAVA in EAST tokamak. Firstly, hybrid simulations with the global kinetic-magnetohydrodynamic (MHD) code M3D-K have been carried out to investigate the beam-driven fishbone in EAST experiment. The results are consistent with the experimental measurement with respect to mode frequency and mode structure. Nonlinear simulations show that the frequency of the fishbone chirps up and down with corresponding hole-clump structures in phase space, consistent with the Berk-Breizman theory. In addition to the low frequency fishbone, a high frequency beta-induced Alfven eigenmode (BAE) is excited during the nonlinear evolution. Secondly, two kinetic-MHD codes, namely MEGA and M3D-K, have been applied to study fast ion driven toroidal Alfven eigenmodes (TAEs) in EAST tokamak. Parameter scans show that the frequency and growth rate of TAEs simulated by the two codes agree well with each other. The analysis of the resonant interaction between the TAE and fast ions shows that the TAE exchanges energy with the co-current passing particles with parallel velocity $|v_∥ |≈V_{A0}/3$ or $|v_∥ |≈V_{A0}/5$, where $V_{A0}$ is the Alfven speed on the magnetic axis. Moreover, the TAE destabilized by the counter-current passing ions has much smaller growth rate than that driven by the co-current ion. Thirdly, the effects of RMPs on the loss and redistribution of passing ions are investigated numerically by the orbit following code GYCAVA for EAST tokamak. The loss fraction and the loss region of passing ions increase with the amplitude of RMPs. For the energetic passing ions, the extra loss induced by RMPs can be comparable to the loss induced by the magnetic drift. The extra loss of passing ions induced by RMPs is related to the drift island structure induced by RMPs and the magnetic drift, and the stochasticity induced by overlap of magnetic islands. The dependence of the loss fraction and loss region on the toroidal mode number of RMPs is related to the safety factor. Finally, the pitch angle and energy of particle can impact the loss of energetic passing ions. These results would provide guidance for future EAST experiments.
Country or International Organization China, People's Republic of
Paper Number TH/1-1

Primary author

Dr Wei Shen (Institute of Plasma Physics, Chinese Academy of Sciences)

Co-authors

Mr Chengyue Liu (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Deng Zhou (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Feng Wang (Dalian University of Technology) Dr Guoqiang Li (Institute of Plasma Physica, CAS) Dr Guoyong Fu (Princeton Plasma Physics Laboratory) Ms Juan Huang (CnIPPCAS) Dr Lei Ye (Institute of Plasma Physics, Chinese Academy of Sciences) Liqing Xu (ASIPP) Dr Nong Xiang (Institute of plasma physics, Chinese academy of science) Prof. Shaojie Wang (University of Science and Technology of China, Hefei, Anhui 230026, China) Mr Siqiang Zhu (University of Science and Technology of China, Hefei, Anhui 230026, China) Dr Xiaotao Xiao (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Y. Todo (National Institute for Fusion Science, Toki, Gifu 509-5292, Japan) Dr Yingfeng Xu (Institute of Plasma Physics, Chinese Academy of Sciences) Mr Youbin Pei (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Youjun Hu (Institute of Plasma Physics, Chinese Academy of Sciences) Dr wenfeng guo (Institute of Plasma Physics, Chinese Academy of Sciences)

Presentation Materials

Paper