High-Speed Videospectroscopy of High-Current Vacuum Arc with CuCr Electrodes and with a Pair CuCr–Mo

The processes of high-current vacuum-arc constriction and plasma formation in near-anode region are highly relevant from the point of view of improving the switching characteristics of vacuum circuit breakers. In this work, using a high-speed video spectroscopic diagnostics in parallel with 2D imaging, the spectral- spatial structure of the arc column and its dynamics during the transition from the diffuse to the anode spot operation mode are studied. Experiments were carried out both with pair of electrodes made of CuCr pseudo-alloy and with a pair of CuCr–Mo electrodes of different polarity. The data obtained clearly demonstrate changes in the charge composition of the plasma of the anode and cathode macrospots in the process of changing discharge forms. In the experiments with CuCr–Mo electrodes, the role of anode evaporation in the formation of the spatial charge distribution in cathode macrospot is clearly demonstrated.