Effects of Magnetic Field on Plasma Confinement of an Ion Thruster Discharge Chamber

This work reports a 2-D full kinetic particle-in-cell plus Monte Carlo collision (PIC/MCC) model for an ion thruster discharge chamber. The model focuses on the influences of the magnetic field strength, the magnetic field topography, and the number of magnetic rings on discharge characteristics. The dependence of plasma behavior and discharge parameters on different magnetic field configurations is analyzed in detail. The simulation results suggest that the enhancement of the magnetic field strength aggravates the confinement of the primary electrons, resulting in higher electron density, ionization rate, and ion density. The primary electrons near the axis undergo numerous inelastic collisions and lose energy, which behaves that the energy of the primary electrons decreases with the increase in the magnetic field strength. Meanwhile, the stronger magnetic field reduces the discharge loss and advances the fraction of the ions extracted into the beam, which reflects favorable discharge efficiency. Furthermore, the improvement of magnetic field topography by adding additional magnetic rings promotes the off-axis of primary electrons and presents a better plasma uniformity. This effort provides insights for understanding plasma confinement and optimizing magnetic field design.