Numerical simulation for near wall conductivity effect on current profiles in the annular channel of Hall-type stationary plasma thrusters

Abstract

Instead of the slab channel model used in previous work, a cylindrical model representing the actual annular channel in Hall-type stationary plasma thrusters is introduced in this paper for the near wall conductivity (NWC) effect on the current profile. The electron dynamics process in the plasma, however, is still described by the same test particle method in current theories where electrons are randomly emitted into the plasma from the wall to simulate electron scattering on the insulating wall. Monte Carlo method is applied to solve the model. The numerical results show that the current density peaks due to NWC near the inner wall of the channel is different from that near the outer wall, a typical annular effect other than in the slab model where the two current peaks are the same, and the ratio of them is approximately the same as the ratio of the inner and outer radii. Besides, the integrated current in the thin layer near the wall grows linearly with the electric field and quadratically with the inversed magnetic field. The peak current profile shifts to the center of the annular channel as the magnetic field decreases. These simulation results are in accord with the experimental data.