Speaker
Yuan Huang
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P4.1039.pdf
Exciting of MHD modes during the penetration of massive gas jet on
J-TEXT tokamak
Y. Huang1, Z. Y. Chen1,*, Qiming Hu2,*, Mingxiang Huang1, Y N Wei1, Daojing
Guo1, Z.J.Yang1, X.M.Pan1,Tong Wang1, Z. F. Lin1, R. H. Tong1, W. Yan1, Z.P.Chen1,
Y. H. Ding1, Y. Liang1 and J-TEXT Team
1
International Joint Research Laboratory of Magnetic Confinement Fusion and
Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and
Technology, School of Electrical and Electronic Engineering, Huazhong University of
Science and Technology, Wuhan, 430074, China
2
Princeton Plasma Physics Laboratory, Princeton NJ 08543-0451, USA
*Corresponding author: Z.Y.Chen and Qiming Hu E-mail: zychen@hust.edu.cn and qhu@pppl.gov
The massive gas injection and the shattered pellet injection of a large amount of
impurities is essential to the mitigation of disruptions on large scale tokamaks. The
deposition of impurities to the center of plasma is the key for the radiation of plasma
energy and runaway suppression. The penetration of gas jet has been found to be limited
by the q=2 surface. The interaction of the gas jet with the rational surfaces has been
studied by scan the plasma current. Experimental results show that injection of massive
argons can cool the plasma from edge to core region and the cooling process is
accompanied by different magnetohydrodynamics (MHD) modes when the gas jet
reach corresponding rational surface. It is observed that with different edge safety
factors, electron density, gas injection can induce different poloidal mode at first. Then
the poloidal mode will traverse lower m (poloidal mode number) MHD activities until
2/1 mode initiated and thermal quench (TQ) was onset. The experimental results show
that the penetration of gas jet across the rational surfaces is faster in the plasmas with
pre-existing large 2/1 tearing mode, which indicates that 2/1 mode plays an important
role in the penetration process.
