Ion Thruster Discharge Modeling with Adjustment of Coefficient of Anomalous Electron Conductivity

Abstract

The results of plasma simulations in a discharge chamber of a Direct Current gridded ion thruster are dependent on the choice of anomalous electron conductivity model. Usually, additional electron diffusion is used to reproduce the experimental conductivity level. Up-to-date, the existing numerical models use different values of the additional diffusion coefficient, and this choice is often nonrigorous or insufficiently justified. In this research, the influence of the additional diffusion coefficient on the results of an axisymmetrical Full-Particle in Cell simulation of plasma in the discharge chamber of a Direct Current gridded ion thruster was investigated. The modeled thruster had a rated power of 3 kW, a thrust of 85 mN, and a specific impulse of 4500 s. The magnitude of the additional diffusion was varied from zero to the value of Bohm diffusion . gave the best agreement of the simulation results with the experimental data for the chosen thruster. A qualitative analysis of the plasma parameter distributions inside the discharge chamber at various anomalous electron conductivity coefficients is also provided. The profile of the ion current density through the ion-optical system obtained in the simulation is in sufficient agreement with experimental data.