Plasma–wall interaction inside a Hall thruster

Abstract

The dynamics of a Hall thruster is investigated numerically in the presence of a plasma–wall interaction. The plasma–wall interaction is a function of the wall potential, which in turn is determined by the secondary electron emission and sputtering yield. In the present work, the effect of secondary electron emission and sputter yield have been considered simultaneously. Owing to disparate temporal scales, ions and neutrals have been described by a set of time-dependent equations while electrons are considered in a steady state. Based on the experimental observations, a third-order polynomial in electron temperature is used to calculate the ionization rate. The changes in the plasma density, potential and azimuthal electron velocity due to the sputter yield are significant in the acceleration region. The change in ion and electron velocity and temperature is small. The neutral velocity, which decreases initially, starts increasing towards the exit consistent with the computed neutral density profile. The results are qualitatively compared with the experiments.