Operating modes of vacuum plasmatrons with hollow cathodes

Results of experimental studies of starting characteristics of vacuum plasma torches in glow discharge mode with switching to abnormal glow discharge and arc discharge are presented. It is demonstrated that if high-frequency current source is used parallel to direct current, ion current is increased and the time of starting mode is reduced. Experimental smelts of tantalum, tungsten, molybdenum, zirconium, and titan were carried out in operating modes with measurement of liquid metal surface temperature in relation to the supplied heating power.