Speaker
Dr
Liang Wang
(Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP))
Description
Managing excessively high divertor power and particle fluxes and related plasma-wall interactions (PWI) is one of the most critical issues for the steady-state operation of the EAST superconducting tokamak and future fusion devices, such as ITER and CFETR. A world record long pulse H-mode operation of 101.2 seconds with H_98=1.1 and total power injection of 0.3 GJ has been successfully achieved in EAST with ITER-like top tungsten (W) divertor, which has steady-state power exhaust capability of 10 MWm-2. The peak temperature of W target T≈500 oC and a heat flux ≈3 MWm-2 was maintained stably. Great efforts have been made to simultaneously control peak heat flux and particle/impurity exhaust towards the long pulse of 100 s time scale. Particle exhaust was optimized by preferentially directing the plasma flow toward the outer target with the ion Bx∇B drift away from the W divertor and improving divertor pumping with the top cryo-pump. Effective power dispersal was achieved by tailoring the three dimensional (3D) divertor plasma footprint using lower hybrid wave (LHW) through induced edge magnetic topology change and broadened plasma wetted area, thus reducing peak heat flux and W sputtering. Extensive lithium coating was employed to lower edge recycling, low-Z impurity content and W sputtering. In addition, divertor detachment in H-mode for PWI handling was achieved for the first time with W divertor in EAST. Compared with previous L-mode in EAST, in H-mode the detachment has a higher density threshold with n_e/n_G~ 0.65. Active feedback control of radiative divertor with neon impurity seeding was successfully achieved with f_rad ~ 18 - 36%, and a slight loss of plasma stored energy ~ 7-11%, offering a promising technique for steady-state divertor radiation and heat flux control. The upgrade plan and status of EAST bottom divertor from graphite to water-cooled W to accommodate more challenging PWI for steady-state H-mode over 400 s and L-mode operation over 1000 s will also be presented.
| Country or International Organization | China, People's Republic of |
|---|---|
| Paper Number | EX/P2-8 |
Primary author
Dr
Liang Wang
(Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP))
Co-authors
Dr
Baonian Wan
(Institute of Plasma Physics, Chinese Academy of Sciences)
Mr
Bin Zhang
(Institute of Plasma Physics, Chinese Academy of Sciences)
Prof.
Bingjia Xiao
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Fang Ding
(Institute of Plasma Physics, Chinese Academy of Sciences)
Prof.
Guangnan Luo
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Guosheng Xu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Mr
Guozhong Deng
(Institute of Plasma Physics, Chinese Academy of Sciences)
Prof.
Houyang Guo
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Jianbin Liu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Prof.
Jiangang Li
(Institute of Plasma Physics, Chinese Academy of Sciences)
Prof.
Jiansheng Hu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Mr
Jichan Xu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Mr
Kai Wu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Ms
Ling Zhang
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Rui Ding
(Institute of Plasma Physics, Chinese Academy of Sciences)
Mr
Wei Feng
(Institute of Plasma Physics, Chinese Academy of Sciences)
Prof.
Xianzu Gong
(Insititute of Plasma Physics, Chinese Academy Sciences)
Dr
Yaowei Yu
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
Youwen Sun
(Institute of Plasma Physics, Chinese Academy of Scienses)
Prof.
Yunfeng Liang
(Forschungszentrum Jülich GmbH, Germany)
Dr
Zhengping Luo
(Institute of Plasma Physics, Chinese Academy of Sciences)
Dr
xiaolan zou
(CEA)
