真空舱背景压力对离子推力器栅极系统工作性能影响的数值模拟

摘要

The background pressure is one of the important factors which affect ion thruster's work performance in ground test. This paper study the influence of background pressure on grid system performance by PIC and MCC. It compares grid system working performance of 20-cm ion thruster under different backpressure, including the particle spatial distribution, potential distribution of grid system and accelerator current, as well as the number of the position of CEX ions colliding to the accelerating grid. The results accord with test result and the effect of background pressure on sputtering corrosion of accelerating grid downstream surface greater than its corrosive effects on the pore wall for the corresponding parameter of 20 cm thruster. considering the cost of test, the ground test vacuum chamber background pressure can be set to the 5x10 Pa.%离子推力器地面寿命试验中,真空舱背景压力是影响推力器性能的重要因素之一.采用二维PIC/MCC方法对栅极系统受背景压力影响进行研究.模拟得到了20 cm离子推力器不同背景压力下栅极系统的电势分布、束流离子空间分布、单位时间内碰撞到加速栅极孔壁和下游表面的交换电荷数目、加速栅极电流等.计算结果与试验测得值很吻合,加速栅极下游表面的溅射腐蚀受背景压力的影响大于其孔壁腐蚀影响,考虑试验成本,可将地面试验真空舱背景压力设为5×104 Pa.