Consequences of balance equations applied to the diffuse plasma of vacuum arcs

By means of balance equations, the partial currents in vacuum arcs are represented by some simple coefficients, and it is shown that the surprising properties of the expanding diffuse arc plasma can easily be explained if the plasma temperature near the cathode is 4.5±0.5 eV (in the case of Cu), i.e., by a factor three times higher than that measured and presumed in most studies. Evidence for this high temperature comes from both the plasma energy balance and the Saha equation