A nonstationary model for vacuum arcs with refractory hot anode

Abstract

A new form of arc, termed the refractory hot anode vacuum arc (HRAVA), was analyzed. The HRAVA has a thermally isolated anode and a cooled cathode. The arc operates initially as a multi-cathode-spot vacuum arc, and material from the cathode spot jets deposits on the anode. During a transition stage, the arc heats the anode and evaporates the material deposited thereon, forming an anode plasma plume. A system of time-dependent equations were formulated and solved for the heat flux from the plasma to the anode surface, heat conduction within the anode, electron energy balance and heavy particle conservation in the anode plasma. The calculations show that the plasma electron temperature decreases while the anode temperature and plasma density increase with time. The model results agree well with previously measured data.