离子发动机加速栅极腐蚀深度的DFF测量与数值模拟

Numerical simulation and DFF measurement of ion thruster accelerator grid erosion depth

使用聚焦深度表面测量(DFF)方法对加速栅极下游表面腐蚀深度进行了测量,并将测量结果与数值模拟结果进行了比较,所使用的数值方法为PIC-Monte Carlo方法.利用数值模拟程序对离子发动机栅极腐蚀进行了数值模拟.以氙为推进剂,栅极材料为钼.用蒙特卡罗方法模拟了氙离子与中性氙原子之间的电荷交换碰撞.模拟得到了加速栅极下游表面离子溅射腐蚀的深度分布,腐蚀模式与"Pits and grooves"模式相吻合.

Particle simulation of ion thruster grids was carried out via particle-in-cell （PIC） method and numerical method for calculating the erosion depth of the accelerator grid downstream surface was developed. Xenon was used as propellant and Molybdenum was used as grid material. Monte Carlo method was adopted to simulate the charge exchange collisions between Xenon ions and atoms. Distribution of erosion depth of the downstream surface of accelerator grid was obtained, and the erosion pattern agreed with the ＂pits and grooves＂ erosion pattern. Depth from focus（DFF）method was used to measure the erosion depth of the downstream surface of the accelerator grid and comparison between the meas- ured and calculated erosion depth was carried out.