20cm口径离子推力器性能建模与仿真

为了分析国内首台通过在轨飞行测试的20cm离子推力器栅极系统束流离子运行特性和推力器性能，针对该推力器栅极系统建立了束流引出二维数值仿真计算模型，利用PIC/MCC数值仿真计算方法，模拟束流引出过程中带电粒子在电场作用下的加速、聚焦与引出、带电粒子与中性原子之间的相互作用、电场和等离子体流场之间的相互耦合等过程。数值计算结果显示，屏栅截获的离子电流约为1.71×10 -4 A，加速栅截获的电流和CEX离子电流分别为0 A和9.11×10 -7 A，因此，加速栅电流的主要来源是冲击到其表面的CEX离子，证明了加速栅电流的主要来源是冲击到其表面的CEX离子，计算的加速栅截获电流与束流电流之比约为0.114%。试验测得推力器运行4000h期间，电子反流极限电压始终为75~90〖KG*9〗V，其变化幅度很小，这意味着中和器发射的电子在栅极系统中的反流不会导致其发生失效。理论计算结果与试验测试值相比，误差约为1.08%。〖JP〗

Numerical Simulation and Analysis of 20cm Ion Thruster Performance

In order to analyze the dynamic features of beam ion and performance of the 20cm ion thruster realized the first flight test in 2012, the beam extraction numerical simulation model is established and the PIC/MCC is used to simulate the process of accelerating and focusing of the beam extraction under the electric field of charged particles, the interaction between charged particles and neutral atoms, the coupling effect between electric field and plasma flow field. The simulation results show that the current acquired by the screen grid and accelerator grid is 1.71×10 -4 A and 0 A respectively. The current of the CEX acquired by the accelerator grid is about 9.11×10 -7 A, and the ratio of the current intercepted and the beam current is about 0.114%, which demonstrates that the most import source of the CEX ion is the current intercepted by the accelerator grid. During the operation of the ion thruster for 4000h, the limited voltage is always 75~90V, the results show that the electron back-stream would not happen while the ion thruster is on operation. The error of theoretical and experimental values is about 1.08%.