Influence of plasma-chemical processes on the parameters of an atmospheric pressure Helium microdischarge

Abstract

This study investigates the influence of plasma-chemical processes on the parameters of an atmospheric pressure (AP) Helium microdischarge. Using a one-dimensional fluid model with both Maxwellian and non-Maxwellian electron energy distribution function (EEDF), we analyze the spatial profile of plasma parameters in a microdischarge with a $0.2mm$ gap. There are significant differences in the recorded rate coefficients for dissociative recombination (DR) and three-body recombination (TR), which are essential for determining the densities of excited atoms and molecules in the high-pressure plasma, where the balance of charged particles is determined by volume recombination. A careful examination of the relevant literature reveals these contradictions. In order to adequately represent the main channels of creation and destruction of excited and charged particles, it is necessary to take into account the atomic states of Helium up to the quantum level $n=4$. The full set of plasma-chemical reactions includes elastic electron collisions, excitation and de-excitation by electrons and atoms, direct and stepwise ionization, associative ionization, molecular excimer creation and destruction, ion conversion, recombination, and radiation. The results reveal that the selected rate coefficients and EEDF form significantly influence the simulation outcomes. This highlights the need to develop improved theoretical models to enhance the control and use of plasma technologies.