离子推力器双阶栅极系统引出性能研究

Aiming at the extraction performance of the dual-stage 4-grid under multiple operating conditions, the focusing and extraction process based on the immersed finite element and particle-in-cell method (IFE-PIC) are studied. The results show that, compared with the conventional grid under the same focusing voltage, the inflection point of over-focus to normal-focus of the dual-stage 4-grid based on the optimal diversion condition moves right, which means its extraction performance becomes worse. Therefore, it is suggested that a small diameter discharge chamber should be used in the design of the dual-stage grid ion thruster to improve the plasma density upstream of the grid, so as to make the dual-stage 4-grid system in normal focusing state. Furthermore, more attention should be paid to the design of dual-stage accelerator grid, such as increasing its aperture diameter, so as to avoid or reduce the direct impact of beam ions.