Numerical Study of Neutral Gas Transport in Linear Plasma Device

Abstract

Possible methods of controlling the neutral gas pressure in a linear plasma device are numerically investigated. For this purpose, the neutral gas transport in argon plasma is calculated by means of Monte Carlo method. The code takes into account the self-elastic collisions along with the elastic neutral–ion and the electron impact ionization collisions. The effects of a baffle plate, the electron temperature, the pump speed, and plasma flow on the neutral density are evaluated within a range of experimental conditions. The baffle plate is found to affect the amount of neutral gas when the electron temperature is low and the plate is located close to a neutral source. As the electron temperature increases, electron ionization strongly enhances the recycling of neutral gas, thus making the role of the baffle plate weaker. It is clarified that the electron ionization is a key factor of the neutral transport in a linear plasma device with low density and low electron temperature.