Plasma flow in a Hall thruster

Abstract

This work represents a two-dimensional (r,z)-3V axisymmetric fully kinetic particle-in-cell/Monte Carlo collision model of the plasmadynamics in the acceleration channel of a stationary plasma thruster. The model includes the process of secondary electron emission from the dielectric walls. In order to allow for a realistic simulation, differently from the previous fully kinetic model using a dummy mass ratio and vacuum permittivity or neglecting radial effects, a geometrical scaling of the channel is applied keeping the main dimensionless physics parameters constant. By this, the problem of the computational limits due to the very fast electron dynamics can be overcome. This model is able to give a clear picture of the plasma flow inside the acceleration channel. The results confirm the existence of an anode sheath with reverse ion flow, an ionization and acceleration region separated by a sonic transition point, and the ion flux distribution hitting the walls. Furthermore, the code is able to reproduce the observed two populations of electrons and to calculate the ion distribution on the exit plane used as input data for plume simulations.