Particle-in-cell simulations for the effect of magnetic field strength on a cusped field thruster

The particle-in-cell plus Monte Carlo method is used to simulate a cusped field thruster. Three different values of magnetic field strength are simulated and convergent results are obtained successfully. The simulation results indicate that with the increase of the magnetic field strength, electron density peak tends to move in the radial direction towards the axis of the discharge channel. The central gap area of electron density is decreased due to the stronger electron confinement, which correspondingly reduces the inevitable central electron leak in the cusped field thrusters. However, it is found that the stronger confinement of electrons reduces electron density near the wall, which increases the neutral gas leak there. It is also validated that the main potential drop in the discharge channel appears near the channel exit. With the enhancement of magnetic field strength, potential drops at separatrices increase correspondingly. At the same time, several potential wells and barriers can be found near the wall, which accords well with recent theoretical and experimental results.