离子推力器加速栅极离子运动规律的数值研究

Three-dimensional numerical study on motion laws of ions in ion thruster optics

以离子推力器栅极组件为研究对象,建立了3维数值模型,应用网格质点法研究了束流离子和电荷交换离子在栅极组件间的运动规律。根据给定的几何和物理参数,模拟得到了栅极组件附近的电势分布、束流离子和电荷交换离子的运动轨迹、速度相空间分布以及加速极电流等。模拟结果表明:加速栅极下游产生的电荷交换离子在电场的作用下会加速撞击加速栅极下游面,是造成加速栅极腐蚀的主要因素;栅极间产生的电荷交换离子会撞击到加速栅极孔壁面,使加速栅极孔逐渐增大。

With the particle-in-cell（PIC） method adopted,a three-dimensional numerical model was developed to study the motion behaviors of beam ions and charge exchange（CEX） ions in the ion thruster optics.Based on the geometric and physical parameters designated,the electric potential in calculation domain,the trajectories and velocities phase space distributions of the beam and CEX ions,and the grid currents were obtained with simulation.The CEX ions produced at the downstream of the acceleration grid will be accelerated by electric field and then impinge on the downstream surface of the acceleration grid,which would be the main reason for acceleration grid erosion.On the other hand,the CEX ions produced between the screen grid and the acceleration grid would impinge on the inner wall of the acceleration grid aperture,which enlarges of the acceleration grid aperture gradually.