基于PIC方法的离子发动机光学系统粒子模拟

Particle simulation of ion thruster optical system based on PIC method

采用单元内粒子(PIC,Particle-In-Cell)方法对离子发动机光学系统进行了等离子体粒子模拟.PIC方法可有效地对等离子体进行粒子模拟,其中电场求解采用SOR(Succes-sive Over Relaxation)方法,离子加速方法采用蛙跳格式.推进剂采用氙,模拟粒子为单核离子.模拟得到了栅极间电势分布、电场强度分布及栅极间氙离子数密度分布.计算结果表明,在所取的光学系统电压参数和几何参数下,粒子束能够顺利通过栅极孔,不会撞击到栅极孔壁上.粒子模拟为今后开展离子发动机光学系统腐蚀机理分析及寿命评估提供了有效的数值方法.

The plasma particle simulation of ion thruster optical system was carried out by the PIC （particle-incell） method. PIC method is an efficient method in plasma particle simulation, in which the SOR（ successive over relaxation） method was adopted to calculate the electric field and the leap-frog method was adopted to accelerate the particles. Xenon was used as propellant and only singly charged Xenon ions was included in the simulation. The simulation results include the distribution of the electric potential between the grids and distribution of the electric field strength, and also the distribution of Xenon ion number density. The simulation results show that under the electrical parameters and the geometric parameters used, the ion beam can get across the grid aperture, with no hits on the grid wall. The simulation of the optical system provided an efficient method to analyze the characteristic of the grid erosion and to evaluate the life time of an ion thruster.