Simulation of Double Cathode Spots with Different Kinds of Protrusions in Vacuum Arc

A three-dimensional asymmetric model has been proposed to study the formation and development of copper cathode spots on different shapes of protrusions and the interaction with a nearby spot in a vacuum arc. The paper compared the morphology and temperature of the erosion process of the spots with spherical protrusions, two different ellipsoidal protrusions and the case of no protrusions as a comparison. Through the simulation calculation, it is found that when there is a large flat and smooth area between the two spots, an obvious liquid metal ridge is formed at the junction of the two spots. When there is no large flat smooth area between two spots due to the existence of some protrusions, the junction of two spots will form a spot-covered morphology. The maximum surface temperature of the cathode appears at the junction of the two spots. The small volume of the bulge formed by the mutual extrusion of the liquid metal leads to the high temperature of the cathode surface.