Effects of magnetic field on gas ionization rate in Hall thrusters

The magnetic field in the channel is one of the core designing factors in Hall thrusters，and it has been exerted a significant effect on both the gas medium ionization rate and the performance. In order to determine the influence law and the mechanism of the gas medium ionization rate caused by the changes of the Bmax （the peak of the magnetic induction intensity）along the channel center line，a numerical model was employed. This model in the present study involved the particle-in-cell model（PIC），the Monte-Carlo-collision model （MCC），and the electron-wall conduction model. To justify and rectify the empirical parameters of the model，a thrust measurement test was conducted in the vacuum chamber，and the comparison of the measurement and calculation results was used to examine the model accuracy. The relative error of the corrected model was less than 7.5%. On the basis above，the influence law and relevant mechanism of the neutral gas ionization rate changing caused by different Bmax has been analyzed by the numerical model. It has been found that there are four phases in the ionization rate vs Bmax curve：slow rise，rapid rise，invariableness and gradual decline. Furthermore，the causing reason is that the electron motion path and the cask effect of the excitation collision exerts respectively a different impact on the ionization collision frequency at different condition of Bmax © 2024 Journal of Propulsion Technology. All rights reserved.