Study of MHD mode and cooling process during disruptions triggered by impurities injection in J-TEXT

Nuclear Fushion

article

Y. Huang¹  Z.Y. Chen¹  Qiming Hu¹  Q. Yu³  Z.H. Jiang¹  Y.N. Wei¹  Pengjuan Su¹  Chengshuo Shen¹  Daojing Guo¹  Z.J. Yang¹  X.M. Pan¹  Mingxiang Huang¹  Qinxue Cai¹  Tong Wang¹  Z.F. Lin¹  R.H. Tong¹  W. Yan¹  Z.P. Chen¹  Y.H. Ding¹  Y. Liang¹  J-TEXT Team¹ 

[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;Chengdu University;Max-Planck-Institut für Plasmaphysik

关键词: disruption;    massive gas injection;    magnetic perturbation;    tokamak;   

DOI  :  10.1088/1741-4326/aae39a

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

The injection of a large amount of impurities is one of the possible ways of mitigating disruption in large-scale tokamaks. The deposition of impurities at the center of the plasma is the key to the radiation of plasma energy and suppression of runaway. The interaction of the gas jet with the rational surfaces has been studied by scanning the plasma current. The experimental results show that the injection of a massive amount of argon can cool the plasma from the edge to the core region, and the cooling process is accompanied by different magnetohydrodynamic (MHD) modes when the gas jet reaches the corresponding rational surfaces. It is observed that with different edge safety factors and electron density, gas injection can induce different poloidal modes at first. Then, the poloidal mode traverses to lowerm(wheremis the poloidal mode number) MHD activities until a 2/1 mode is initiated and a thermal quench is started. The experimental results show that the penetration of a gas jet across the rational surfaces is faster in the plasmas with pre-existing large 2/1 tearing modes, which indicates that the 2/1 mode plays an important role in the penetration process. Disruptions triggered by supersonic molecular beam injection display a slower cooling process compared with massive gas injection, which can be divided into four stages. The dominant poloidal mode transition fromm   =  3 tom   =  2 is associated with electron temperature recovery.

【 授权许可】

Unknown