Numerical simulation of plasma power deposition on hollow cathode walls using particle-in-cell and Monte Carlo collision method

Abstract

The plasma parameters and power deposition on the walls in an orificed hollow cathode (HC) were investigated by employing the particle-in-cell (PIC) numerical method combined with Monte Carlo collisions. A new plasma power-deposition model based on the particle-wall interactions is presented. The distributions of plasma potential, plasma density, and power deposition from particles bombarding the wall surface were calculated in the PIC simulation, for the HC operating in the diode regime with a discharge current of 10.0 A and a gas flow rate of 3.5 sccm. The simulation results suggested that the electrons exhibited non-Maxwellian electron energy distributions in the insert region and that quasi-neutrality was violated outside the bulk plasma system. In addition, the results showed that the plasma power deposited on the emitter, on the upstream surface of the orifice plate, on the orifice inner wall, and on the downstream surface of the orifice plate was in the ratio of about 4:3:1:2. The results also indicated that charge exchange collisions can dramatically weaken power deposition from plasma ions.