Near-cathode region of contracted discharge at MHD-generator metallic electrodes

The parameters in the arc-discharge base are investigated, taking into account processes in the plasma near the cathode, in a model allowing for the effect of a thin-film deposit on the electrode (copper, steel) surface. It is shown that when the mean electrode temperature is increased above $900$ K the current density in the arc base falls considerably, whereas the arc-base temperature changes insignificantly. There is a discussion of the mechanism of electrode erosion, associated with the melting and evaporation of the metal.