Steady-state model of a refractory hot anode vacuum arc

A plasma model for a new mode of a hot refractory anode vacuum are configur ation is presented. The are is sustained between a copper cathode and a hot graphite anode separated by a 1 cm gap. The cathode operates in the multic athode spot regime, while the hot graphite anode back-evaporates the materi al flux arriving from the cathode. The interelectrode plasma expands radial ly from the gap. A system of equations for the heat flux from the plasma to the anode and fo r the anode heating is proposed. The anode heat flux is obtained by solving a system of equations for plasma energy balance, plasma mass conservation and current continuity in the interelectrode gap. Plasma electron temperature, plasma density, anode drop potential and anode temperature are calculated Good agreement is found between the calculated and measured anode temperature and plasma parameters. Thus, at steady state the calculated and measured effective anode voltage is about 6 V and the e lectron temperature is about 1 eV.