Effect of anisotropic non-Maxwellian electron distribution function on plasma-wall interaction in Hall thrusters

¹ Lab of Plasma Propulsion, Harbin Institute of Technology - Mail Box 458, Harbin 150001, China
² Institute of Power Engineering, Chongqing University - Chongqing 400030, China
³ State Key Lab of Nuclear Physics and Technology, School of Physics, Peking University - Beijing 100871, China

^(a) yudaren@hit.edu.cn

Received: 6 September 2012
Accepted: 23 October 2012

Abstract

Due to the extreme plasma conditions in Hall thrusters, such as electron temperature anisotropy and non-Maxwellian electron distribution function (EDF), understanding the plasma-wall interaction is a very challenging task. This letter is attempting to study this issue with a two-dimensional particle-in-cell model. It is found that the anisotropic non-Maxwellian EDF makes the electron temperature threshold for the appearance of a spatial oscillation wall sheath much lower than the Maxwellian EDF does. Furthermore, even though the sheath potential drop in the anisotropic non-Maxwellian case is found much smaller than those in Maxwellian cases, the plasma-wall interaction becomes much weaker since the anisotropic non-Maxwellian EDF is depleted at high energies.