Effects of the peak magnetic field location on discharge performance of a 100-W Hall thruster with large gradient magnetic field

Abstract

Traditional Hall thrusters can ionize gas inside the channel and accelerate ions outside it by moving the peak magnetic field out of the channel, which improves the thruster performance. In this study, the effects of the peak magnetic field location on the discharge characteristics of a 100-W Hall thruster with large-gradient magnetic field were investigated by changing the ratio of the magnetic field intensity at the channel exit to the peak magnetic field intensity (Brexit/Brmax). The experimental results show that the discharge performance decreases significantly when Brexit/Brmax < 1. Moreover, the PIC numerical simulation and neutral gas simulation results demonstrate that the ionization rate inside the channel reduces and the ionization proportion outside the channel increases when Brexit/Brmax decreases, thereby reducing the performance. When Brexit/Brmax = 1, under the anode flow of 5.5 sccm and discharge voltage of 250 V, the thrust, anode specific impulse, propellant utilization efficiency, and anode efficiency of the 100-W thruster were 6.4 mN, 1210 s, 68.9%, and 38.5%, respectively, which represent respective improvements of 16.2%, 16.4%, 13.0%, and 30.0% (relative value) compared with the condition when Brexit/Brmax = 0.9. These results provide a reference for the performance optimization of 100-W Hall thrusters with a large-gradient magnetic field.