Electrode Phenomena in Plasma Sources

Abstract

Electrodes play a key role in arcs and are often the limiting component in plasma arc technology. The description of the interaction between arcs and the surface of the electrodes is rather difficult due to changes in the phenomena dominating in different parameters ranges, especially at different pressures, currents, and current densities. Electrodes are the interfaces between a plasma at temperatures above 7000–8000 K (below which its electrical conductivity is too low to sustain an arc) and a solid material at a temperature below its point of vaporization (4000 K at the most). The cathode has to emit electrons for establishing the arc, while the anode is passive, collecting electrons to maintain the current continuity