The objective of this study is to investigate the effects of a magnetic field gradient on the performance of a magnetically shielded Hall thruster. The Particle-in-cell with Monte Carlo collision method (PIC-MCC) is used to simulate the discharge process of the thruster. The performance and plasma characteristics are obtained in conditions with different magnetic field gradients by numerical simulations. As the maximum of the gradient is increased from 1.2 to 3.33 T/m, the electron number density near the channel exit decreases, which leads to less ionization and a weaker radial electric field. As a result, the thrust and specific impulse are decreased, while the plume divergence angle is reduced.

The self-induced magnetic field in a pulsed plasma thruster (PPT) with flared electrodes is investigated for a better understanding of the working process and the structural design of the thruster. A two dimensional model of the magnetic field is built and is validated by comparing the simulated results with the experimental results in literature. The magnetic flux density in the discharge channel during the working process is presented and analyzed regarding the electrodes structures. The calculated magnetic field flux density decreases from 0.8 T at the upstream to 0.1 T and below at the downstream in the discharge channel (68 J). The peak of the magnetic flux density over time lags behind the current peak, which provides evidence for the existence of a moving plasma sheet in the discharge process. The magnetic field induced by the current in the extra bending part of the anode enhances the Lorentz force which acts on the charged particles near the propellant. Finally, the geometric study indicates that the electromagnetic impulse bit does not monotonically increase with the flared angle of the electrodes, instead, it reaches a maximum at a certain flared angle, which could provide significant suggestions for structural optimization.