Thermal Analysis of an Arc-Heater Electrode with a Rotating Arc Foot

Analytic formulations are presented for the analysis of an arc-heater electrode with a rotating arc foot. Two limiting cases, a smoothly rotating arc foot and an arc foot that jumps between multiple sticking points, are analyzed. For each case the temperature distribution for a copper electrode is obtained for the plausible range of operating conditions. It is shown that the smoothly rotating arc foot is an extremely safe mode of operation, whereas the jumping arc foot produces excessively high electrode surface temperatures. It is suggested to eliminate arc-foot rotation and rely on a distribution of fixed electrodes with stationary arc attachment to avoid electrode failure at high current.