High-voltage stage of a vacuum arc

An elementary theory of the cathode region at the high-voltage stage of an arc discharge is proposed. The theory is based on the balance equations for the particles in an active plasma layer, the power balance at the cathode, and the equation for the Richardson-Dushman electron emission with allowance for the Schottky effect. The most characteristic features of this type of discharge are considered. A non-Langmuir cathode sheath model is proposed for a low-voltage arc on a tungsten electrode.