Two-dimensional simulation of an Ar/H2 direct-current discharge plasma

We created a two-dimensional, mathematical fluid model of a plasma in a spherical direct-current (DC) glow-discharge chamber based on the finite-element method (FEM) using the commercial FEM solver COMSOL Multiphysics. The model is based on the Boltzmann transport equation, and we solved it to simulate the transient physical characteristics of an Ar/H2 glow-discharge plasma, including the distributions of electron density, electrical potential, electron temperature, and other physical characteristics in the reaction chamber. We simulated a 5%H2/95%Ar DC glow discharge at 500 V and 2 Torr, and the results show that the electron density is distributed between the anode and the cathode, with a maximum electron density of 2.76 × 1015 m−3 and a maximum electron temperature of 5.37 eV. We also studied the effects of the discharge voltage and pressure on the electron density. The mathematical model simulates well the variation of the electron density in the chamber, and it shows that the electron density increases with increasing pressure or driving voltage.