Unified modelling of near-electrode non-equilibrium layers in high-pressure arc discharges

This paper studies the current transfer through near-electrode layers on the basis of direct numerical simulation of the layer, without dividing it into sub-layers with different properties. Governing equations include equations of conservation and transport equations for the ions, the atoms, and the electrons, equations of energy for the electrons and the heavy particles, and the Poisson equation. The equations are solved numerically in 1D without any further simplifications, in particular, without explicitly dividing the near-cathode layer into a space-charge sheath and quasi-neutral plasma. Results of numerical simulation of near-cathode and near-anode layers in an atmospheric-pressure argon arc and in high-pressure mercury arcs with tungsten cathode are given: distributions of plasma parameters across the layer, current-voltage characteristics, energy flux from the plasma to the cathode.