Melt formation on the graphite electrode surface in a diffusive arc discharge

We present the results of investigation of a discharge with a current of $15$–$200$ A between graphite electrodes at argon pressure of $10$–$90$ kPa after long-term specimen heating by the DC at a temperature of about $3$ kK. The change in the electrode shape is evidence of the existence of a melt film on the electrode surfaces at the temperature of $3.3$–$3.5$ kK. The anode vaporization velocity is in agreement with the data on the pressure of the saturated vapor of the atomic carbon.