HT-7 Tokamak离子回旋波和低杂波等离子体逃逸电子行为研究

Runaway electrons behaviors during ion cycolotron range of frequency and lower hybrid wave plasmas in the HT-7 Tokamak

HT-7Tokamak拥有离子回旋波(ICRF)和低杂波(LHW)两套加热系统.ICRF主要对加热离子有比较好的加热效果,LHW则主要是通过电子Landau阻尼加热电子.除此之外,在ICRF和LHW协同加热的条件下,可以对等离子体产生更有效的加热效果,增加等离子体的聚变反应截面,增加聚变中子产额.本文报道了LHW对改善ICRF和等离子体耦合的重要作用,ICRF和LHW加热等离子体中电子温度随时间的演化过程;计算了放电过程中电子逃逸的阈值能量,分析了逃逸电子的产生过程,以及放电过程中的中子产额.研究结果发现:一定功率的LHW有助于改善ICRF和等离子体之间的耦合.ICRF和等离子体耦合情况的不同将对逃逸电子的产生率造成影响.ICRF的投入有利于增加等离子体聚变的反应截面,增加Tokamak等离子体的聚变中子产额。

HT-7 Tokamak is equipped with a lower hybrid wave（LHW） system and an ion cyclotron range of frequency（ICRF） system.ICRF can accelerate ions effectively,while LHW can accelerate electrons effectively.The generation of runaway electrons during the LHW and ICRF plasmas,as well as the time evolution of electron temperature during the ICRF and LHW plasmas was investigated in this paper.The runaway critical energy for runaway electrons was also calculated according to the experimental data.It was observed that the combination of ICRF and LHW can produce a higher heating efficiency and a better coupling between ICRF and plasmas if the power of LHW exceeds a critical value.Therefore,the generation of runaway electrons and fusion neutrons are affected by ICRF.