Improvements for drift-diffusion plasma fluid models with explicit time integration

TL;DR

This paper introduces an explicit time integration method for drift-diffusion plasma fluid models, addressing high conductivity limitations and unphysical electron diffusion near strong gradients, with comparative analysis of existing and new correction approaches.

Contribution

It presents a fully explicit method to overcome time step limitations and compares approaches to correct unphysical electron diffusion in plasma models.

Findings

The explicit method outperforms semi-implicit methods in efficiency.

New correction approaches reduce unphysical ionization near gradients.

Implementation details facilitate adoption of improved models.

Abstract

Drift-diffusion plasma fluid models are commonly used to simulate electric discharges. Such models can computationally be very efficient if they are combined with explicit time integration. This paper deals with two issues that often arise with such models. First, a high plasma conductivity can severely limit the time step. A fully explicit method to overcome this limitation is presented. This method is compared to the existing semi-implicit method, and it is shown to have several advantages. A second issue is specific to models with the local field approximation. Near strong density and electric field gradients, electrons can diffuse parallel to the field, and unphysically generate ionization. Existing and new approaches to correct this behavior are compared. Details on the implementation of the models and the various approaches are provided.