Numerical Analysis of the Influence of Evaporation of the High- and Low-Melting-Point Anode Materials on Parameters of a Microarc Discharge

Abstract

We present the results of numerical studies of the influence of evaporation of anode material on the main characteristics of an arc discharge. Calculations were carried out for an arc discharge in helium as a buffer gas with high-melting-point (using graphite as an example) and low-melting-point (using copper as an example) anodes. The dependences of the main arc-discharge parameters on current density are presented. It is demonstrated that intense evaporation of particles of the anode material into the discharge gap occurs upon reaching the melting point of the anode surface. As a result, the plasma-forming ion is replaced, i.e., the carbon ion in the case of the graphite anode or a copper ion in the case of the copper anode becomes dominant. In the process, a jump in the potential is observed in the dependence of voltage on current density (the volt–ampere characteristic, VAC). Distribution of the main plasma parameters along the discharge gap is presented for different points in the VAC.