Two-dimensional model of orificed micro-hollow cathode discharge for space application

Abstract

In this paper, we describe results of self-consistent two-dimensional (x-z) particle-in-cell simulations, with a Monte Carlo collision model, of an orificed micro-hollow cathode operating in a planar diode geometry. The model includes thermionic electron emission with Schottky effect, secondary electron emission due to cathode bombardment by the plasma ions, several different collision processes, and a non-uniform xenon background gas density in the cathode-anode gap. Simulated results showing behavior of the plasma density, potential distribution, and energy flux towards the hollow cathode and orifice walls, are discussed. In addition, results of simulations showing the effect of different Xe gas pressures, orifice size, and cathode voltage, on operation of the micro-hollow cathode are presented. V C 2013 AIP Publishing LLC.

Influence of Xe2+ ions on the micro-hollow cathode discharge driven by thermionic emission

“…9. The 2D plots of steady-state potential distribution and plasma species densities are presented in Fig.…”

“…The angles after collision are calculated using the equations described in Ref. 9. If reaction #8 occurs, the excited atom is removed from the simulations and the colliding electron obtains an additional energy that is equal to the energy of Xe atom excitation.…”

“…9 This model is based on the 2D Cartesian module of the open-source WARP 14 PIC code. In order to study the influence of ionized dimers Xe 2 þ on the micro-hollow cathode discharge in the geometry shown in Fig.…”

“…In a recent paper, 9 we reviewed the Particle-in-Cell (PIC), fluid, and hybrid models used by different groups for analyzing thermionic emission HC operation. It is important to note that these models consider three plasma species (electron, ion, and neutral), and excited atoms or multi-charged ion species were not taken into account.…”

“…[4][5][6][7][8][9] Depending on the technological application, HC high current discharge is ignited and sustained by different electron emission mechanisms, namely, field, secondary, photo, or thermionic emission, or a combination of these electron emission mechanisms. The HCs driven by thermionic emission are used in applications related to electric propulsion; [4][5][6][7][8][9] we will consider only this type of HC below.…”