On the effect of an axial magnetic field on the high-current vacuum arc

Vacuum arcs in axial fields B/sub x/ are modeled as cathode-spot jets combining into a common current channel. The model provides a novel condition for the observed transition from the falling to the rising branch of arc voltage versus H/sub x/. The smooth transition corresponds to the B/sub x/ for which the jet mixing occurs at the anode, on average. These two-dimensional calculations agree well with experiments.