A non-stationary model for vacuum arcs with a refractory hot anode

A new form of are, termed the refractory hot anode vacuum are (HRAVA), was analyzed. The HRAVA has a thermally isolated anode and a cooled cathode. The are operates initially as a multi-cathode-spot vacuum are, and material from the cathode spot jets deposits on the anode. During a transition stage, the are 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 plume. 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.