State of the theory of vacuum arcs

A review of vacuum are phenomena including the cathode and anode processes with cold and hot electrodes as well as the processes in the interelectrode plasma is presented. In the case of cold electrodes, the current continuit y mechanism, the nature of mass loss, spot motion, plasma jet generation in the spots, and the cathode potential drop are reviewed. The explosive and gas-dynamical models of cathode spot operation are described. In the case o f hot electrodes, the diffuse current continuity mechanism is analyzed and a model for electron-current fraction calculation in discharge with cathode -anomalous electron emission is proposed. The present state of electrical a nd plasma characteristics of high-current arcs in magnetic fields are discu ssed.