Abstract: Electron backstreaming is one of the most important failure modes, which determines the operating lifetime of the ion thruster. To gain the sensitivity effect of kinds of parameters on the electron backstreaming failure mode, and obtain the accelerator stress, and provide data and guidance of the ground accelerator lifetime experimental test and long lifetime optimization design, this paper used the Hybrid-PIC-MCC method and established a 3-grid system simulation model to study the comparison of effect sensitivity of the ground vacuum chamber background pressure, the screen grid potential, the accelerator grid potential, the screen-accelerator grid gap, the plasma density upstream the screen grid and the mass utilization efficiency. Simulation results showed that the ground vacuum chamber background pressure was the first-choice accelerator stress for the accelerator lifetime experimental test. Among the geometric and operating parameters, the mass utilization efficiency was the most sensitive one. Other stress factors include the screen grid potential, the plasma density upstream the screen grid, the accelerator grid potential, and the screen-accelerator grid gap.

Key words: Ion thruster;3-grid system;Hybrid-PIC-MCC method;Sensitivity

摘要： 电子反流失效模式是离子推力器关键失效模式之一，决定推力器工作寿命。为明确各参数对电子反流失效模式的影响程度，确定加速应力，为地面加速寿命实验验证方案和长寿命优化设计提供数据支持，采用Hybrid-PIC-MCC（Particle in Cell- Monte Carlo Collision）方法，构建了三栅极系统数值仿真模型。采用模型研究了地面真空舱本底压力、屏栅电压、加速栅电压、屏栅与加速栅间距、屏栅上游等离子体密度和放电室工质利用率等参数的影响敏感度对比。研究结果显示,真空舱本底压力可以作为加速寿命试验的首选加速应力，在推力器结构和工作本征参数中工质利用率为最敏感应力，其次是屏栅电压、屏栅上游等离子体密度、加速栅电压、屏栅和加速栅间距。

关键词: 离子推力器;三栅极系统;Hybrid-PIC-MCC方法;敏感度