Computational study of microdischarges driven by electron beam injection with particle-in-cell/Monte Carlo collision simulations

Abstract

Microdischarges (MDs) have attracted increasing attention recently due to their widespread applications. The electron beam injection as an external source can affect the formation and characteristics of microdischarges. Aimed at exploring the kinetic properties of the atmospheric-pressure microdischarges purely driven by electron beam injection without external voltage, the one-dimensional implicit particle-in-cell/Monte Carlo collision model is developed. The monoenergetic electron beam is injected from the left electrode with a current of 0.001–0.05 A and an emission energy of 20–80 eV. It is found that similar to voltage and current-driven MDs, electron beam driven MDs can sustain steady glow discharge with high density (1021–1022m−3) but has much lower plasma potential (∼0.15−0.30 V) and electron temperature (<1 eV) due to the absence of an external field. The electron energy distribution function is composed of a low-energy group with two-temperature distribution and a high-energy group with a discrete distribution. In addition, the injected electron beam current and energy can influence the plasma properties significantly, such as plasma density, electron temperature, plasma potential, etc. The characteristics of ion bombardment can also be modulated by the beam energy and current, resulting in achievement of low energy and high flux. By enlarging the gap between the electrodes, the parameter difference on both sides can be realized.