HT-7托卡马克等离子体密度调制实验中的逃逸电子行为

Runaway electron behavior in plasma density modulation experiments in HT-7 Tokamak

在HT-7托卡马克的等离子体密度调制实验中,通过对欧姆和低杂波电流驱动两种放电条件下等离子体逃逸电子辐射行为的研究,验证了非准稳态等离子体中逃逸电子的产生机制,研究了欧姆和低杂波电流驱动两种放电条件下的大量充气对等离子体整体约束性能的影响。研究结果发现:放电过程中额外的大量工作气体的充入使等离子体偏离了准稳态,逃逸电子初级产生机制和次级产生机制准稳态的假设条件被打破,这时候需要利用非准稳态条件下修正后的逃逸电子归一化阈值速度来解释逃逸电子的辐射行为;同时也发现放电过程中额外的大量工作气体的充入将使等离子体的整体约束性能变差。

The generation mechanism of runaway electrons in non-quasi-stable state plasmas and the influence of massive gas injection on the confinement of plasmas are investigated in ohmic and low hybrid current drive （LHCD） plasma density modulation experiments in HT-7 Tokamak. It is found that massive gas injection during the discharge made the plasma from quasi-stable state turn into non-quasi-stable state in which the quasi-stable state assumption condition of Dreicer mechanism and secondary mechanism （avalanche） of runaway electron generation does not exist. Therefore, it is necessary to use the normalized critical ve- locity to explain the runaway electron behavior in non-quasi stable state plasmas. It is also found that the plasma confinement be- came poor during massive gas injection in the plasma density modulation experiments in HT-7 Tokamak.