Investigating near-anode plasma layers of very high-pressure arc discharges

Abstract

Numerical and experimental investigation of near-anode layers of very high-pressure arcs in mercury and xenon is reported. The simulation is performed by means of a recently developed numerical model in which the whole of a near-electrode layer is simulated in the framework of a single set of equations without simplifying assumptions such as thermal equilibrium, ionization equilibrium and quasi-neutrality and which was used previously for a simulation of the near-cathode plasma layers. The simulation results support the general understanding of similarities and differences between plasma–cathode and plasma–anode interaction in high-pressure arc discharges established in preceding works. In particular, the anode power input is governed primarily by, and is approximately proportional to, the arc current. In the experiment, the spectral radiance from the electrodes and the near-electrode regions in xenon arcs was recorded. The derived total anode power input and near-anode plasma radiance distribution agree reasonably well with the simulation results.