On the accuracy and reliability of different fluid models of the direct current glow discharge

Abstract

We developed and tested 2D “extended fluid model” of a dc glow discharge using COMSOL MULTIPHYSICS software and implemented two different approaches. First, assembling the model from COMSOL’s general form pde’s and, second, using COMSOL’s built-in Plasma Module. The discharge models are based on the fluid description of ions and excited neutral species and use drift-diffusion approximation for the particle fluxes. The electron transport as well as the rates of electron-induced plasma-chemical reactions are calculated using the Boltzmann equation for the EEDF and corresponding collision cross-sections. The self-consistent electric field is calculated from the Poisson equation. Basic discharge plasma properties such as current-voltage characteristics and electron and ion spatial density distributions as well as electron temperature and electric field profiles were studied. While the solutions obtained by two different COMSOL models are essentially identical, the discrepancy between COMSOL and CFD-ACE+ model solutions is about several percents and caused by the difference in the models due to undocumented details in the software packages. We also studied spatial distributions of particle fluxes in discharge plasma and identified the existence of vortex component of the discharge current.

Atomic oxygen patterning from a biomedical needle-plasma source

“…In the present work, the commercial finite element partial differential equation solver COMSOL Multi-physics a) Electronic mail: kellys77@mail.dcu.ie (version 4.3a) 20 is used to find a mutually consistent solution for the reacting gas flow (which is assumed to be laminar) and the plasma discharge 6,20 . Initially, mass and momentum continuity equations (compressible Navier-Stokes) are coupled to a mass transport equation and solved in a steady state manner for a profile of the helium-air mixture.…”

Modeling Plasma via Electron Impact Ionization

“…Chemical kinetics models for low-temperature plasma generation span a very wide range of complexity, from the detailed description by Elisson et al [23], Bogdanov et al [30] to simplified approximations by Solov'ev et al [31], Singh et al [32], Pancheshnyi et al [33], and Rafatov et al [34]. All these approaches are rational and the fidelity to physics in computational simulation for non-equilibrium chemical reactions is solely dependent on the empirical rate constants.…”

Two-dimensional hybrid model for a glow discharge: comparison with fluid and kinetic (particle) models, reliability and accuracy

“…Within the fluid method, the particle species (electrons, ions, and neutrals) are considered as fluids described by the continuity equations with drift-diffusion approximation for particle fluxes. Fluid models usually employ a local field approximation (LFA), according to which transport coefficients as well as the ionization rate are determined as functions of the reduced electric field [3,4,5]. Fluid methods in general are capable to describe basic qualitative properties of plasma.…”