负径向电场对带电粒子俘获率影响的数值模拟

Numerical Simulation of Influence of Negative Radial Electric Field on Charged Particle Capture Rate

本文采用数值方法求解Grad-Shafranov方程反演EAST典型长脉冲放电实验(炮号33068)的平衡位形和磁场分布,进而结合粒子在托卡马克电磁场中的运动方程,模拟氘离子在负径向电场存在时的运动轨迹,并统计不同负径向电场下的氘离子俘获率。结果表明:随负径向电场的增大,氘离子轨迹由扩张通行轨迹向外翻香蕉轨迹再向内翻香蕉轨迹,最后向压缩通行轨迹演变;氘离子俘获率随负径向电场的增大而减小,氘离子初始速度越小,其变化越大。

The equilibrium configuration and magnetic distribution were achieved by numerically solving Grad-Shafranov equation in the typical long-pulse discharge(shot 33068)on EAST in this paper.Considering the motion equation of particles in magnetic field,deuterium ion orbit was simulated when negative radial electric field existed,and also,the deuterium ion capture rate was statistically calculated.The results indicate that the deuterium ion orbit converts from expansion passing particle orbit to expansion trapped particle orbit firstly,and then,to compression trapped particle orbit,and further,to compression passing particle orbit when the negative radial electric field becomes large.The deuterium ion capture rate decreases with the increase of negative radial electric field,and the smaller the initial velocity of deuterium ion,the greater the change.