Anode Temperature Evolution in a Vacuum Arc With a Blackbody Electrode Configuration

The anode in a vacuum arc with a blackbody assembly was measured as a function of time. A 30-mm-diameter Cu cathode and a hollow Ta anode, 50 mm in diameter, were used for a plasma cavity. Cu plasma was ejected through an array of 250 holes of 0.6 mm diameter in the anode. The arc currents were I = 175, 200, and 225 A and the arc duration was 160 s. The anode temperature was measured using high-temperature thermocouples in the top and side of the anode. The anode temperature increased sharply during a transient time of ~70-90 s and then, it slightly increased with time up to 160 s reaching at 1650 K (I = 175 A) and 1850 K (I = 225 A) at the top, and 150-200 K less in the side.