Moment fluid equations for ions in weakly-ionized plasma

TL;DR

This paper introduces a new one-dimensional fluid model for ions in weakly-ionized plasma that improves collision term approximation and includes ion energy, showing good agreement with particle-in-cell/Monte Carlo simulations.

Contribution

The paper presents a novel fluid model with enhanced collision term approximation and ion energy consideration, validated against detailed kinetic simulations.

Findings

Fluid model aligns well with PIC/MC simulation results across various conditions.

Improved collision term approximation enhances model accuracy.

Inclusion of ion energy equation provides better plasma behavior predictions.

Abstract

A new one-dimensional fluid model for ions in weakly-ionized plasma is proposed. The model differs from the existing ones in two aspects. First, a more accurate approximation of the collision terms in the fluid equations is suggested. For this purpose, the results obtained using the Monte-Carlo kinetic model of the ion swarm experiments are considered. Second, the ion energy equation is taken into account. The fluid equations are closed using a simple model of the ion velocity distribution function. The accuracy of the fluid model is examined by comparing with the results of particle-in-cell/Monte Carlo simulations. In particular, several test problems are considered using a parallel plate model of the capacitively coupled radio-frequency discharge. It is shown that the results obtained using the proposed fluid model are in good agreement with those obtained from the simulations over a wide range of discharge conditions. An approximation of the ion velocity distribution function for the problem under consideration is also discussed.