Speaker
Prof.
Yunfeng Liang
(Forschungszentrum Juelich GmbH)
Description
ELM mitigation has been observed on the Experimental Advanced Superconducting Tokamak (EAST) when lower hybrid waves (LHWs) are applied to H-mode plasmas sustained mainly with ion cyclotron resonant heating (ICRH). This has been demonstrated to be due to the formation of helical current filaments (HCFs) flowing along field lines in the scrape-off layer induced by LHWs. Because of the geometric effect of the LHW antenna, the perturbation fields induced by the HCFs are dominated by the n=1 components, where n is the toroidal mode number. In comparison to previous RMP ELM mitigation experiments, using a set of fixed in-vessel coils, ELM mitigation with LHWs on EAST is achieved with a wider range of q95. This is because the HCFs induced by the LHWs flow along the magnetic field lines in the SOL, thus the helicity of the HCFs always closely fits the pitch of the edge field lines whatever the value of the plasma edge safety factor.
Splitting of the outer divertor strike point during LHWs has been observed similar to previous observations with RMPs. The change in edge magnetic topology has been qualitatively modelled by including the HCFs in a field line tracing code. The results show a strong modification of the plasma edge topology dependent on the edge safety factor as well as the amplitude of currents flowing in these filaments. This can qualitatively explain the experimental observations of SP splitting.
| Country or International Organisation | Germany |
|---|---|
| Paper Number | EX/P3-8 |
Primary author
Prof.
Yunfeng Liang
(Forschungszentrum Juelich GmbH)
Co-authors
Dr
Baonian Wan
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Biao Shen
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Bo Lv
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Bojiang Ding
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Eric Gauthier
(CEA, IRFM France)
Dr
Fukun Liu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Guosheng Xu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Prof.
Houyang Guo
(Institute of Plasma Physics, Chinese Academy of Sciences)
Mr
Huiqian Wang
(Institute of Plasma Physics,Chinese Academy of Sciences)
Dr
Jiafang Shan
(Institute of Plasma Physics, Chinese Academy of Sciences)
Prof.
Jiangang Li
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Jiansheng Hu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Jinping Qian
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Kaifu Gan
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Liang Wang
(Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP))
Dr
Liqun Hu
(Institute of Plasma Physcis, Chinese Academy of Sciences)
Dr
Long Zeng
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Mao Wang
(Institute of Plasma Physics, Chinese Academy of Sciences)
Mr
Michael Rack
(Forschungszentrum Juelich, Germany)
Mr
Ning Yan
(Association EURATOM/DTU Physics, Roskilde, Denmark)
Dr
Peter Denner
(Forschungszentrum Juelich, Germany)
Dr
Ran Chen
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Shoubiao Zhang
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Tao Zhang
(Institute of Plasma Physics, Chinese Academy of Sciences)
Mr
Tonghui Shi
(Institute of Plasma Physics, Chinese Academy of Sciences)
Prof.
Ulrich Samm
(Forschungszentrum Juelich, Germany)
Prof.
Xianzu Gong
(Insititute of Plasma Physics, Chinese Academy Sciences)
Dr
Yinxian Jie
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Youwen Sun
(Institute of Plasma Physics, Chinese Academy of Scienses)
Dr
Zhenwei Wu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
xiaolan zou
(CEA)
Mr
yumin Wang
(Institute of plasma physics, Chinese Academy of Sciences)
