负径向电场对荷电粒子运动的影响及其数值模拟

Influence of negative radial electric field on charged particles and numerical simulation

从负径向电场产生的电漂移改变荷电粒子运动的极向运动速度着手,推导出在负径向电场存在时安全因子的表达式,分析了安全因子对荷电粒子漂移位移和运动轨迹的影响。建立了在负径向电场条件下,荷电粒子在梯度磁场和曲率磁场中运动数学模型。通过数值模拟,获得了通行粒子、香蕉粒子的漂移位移和运动轨迹所呈现出的新特点和规律:负径向电场改变了荷电粒子的最大漂移位移。当荷电粒子的极向运动速度增加时,最大漂移位移减小,反之增大;改变了荷电粒子的运动轨迹,通行粒子的轨亦可能变为香蕉粒子的轨迹,香蕉粒子的轨迹可能变为通行粒子的轨迹,当电场达到足够的强度时,均成为在极向上顺时针运动的通行粒子轨迹。

In light of poloidal motion velocity changed by electric drift, the paper derives the equation for safety factor when negative radial electric field existed, analyzes the influence of safety factor upon the drift displacement and motion orbit of charged particles, and established mathematical models for charged particles moving in the gradient and curvature magnetic fields. Through numerical simulation, the paper concludes new features and rules about drift displacement and motion orbits of both transit and banana particles. Negative radial electric field changes the maximum drift displacement of charged particles. When the poloidal velocity of charged particles increases, the maximum drift displacement decreases and contrarily it increases. Change the orbit of charged particles, the obit of transit particles may become that of banana particles and vice versa. When the electric field reaches the intensity high enough, they both become orbits of transit particles moving clockwise poloidally.