Modeling and simulation results of a high current vacuum arc in a transverse magnetic field

This paper presents the results of simulations using a model that describes constricted high current (>15 kA) vacuum arcs driven by a transverse magnetic field in a 2D configuration (parallel rail electrodes). The simulations investigate the influence of the electrode gap distance on the arc motion. It is found that faster arc velocities are obtained for larger gaps. For large gaps (ges5 mm), the Lorentz forces and pressure gradients acting on the plasma jets originating from the hot electrodes strongly affect the arc structure: the arc tends to expand on a longer distance and can efficiently prepare the next current attachment. The trend seen in the simulation results compares qualitatively well with the experimental results found in the literature. Another investigation of the effect of an arc returning several times to the same points on the electrodes for a fixed DC current shows that the minimum surface temperature increases during the first four turns, before stabilizing at a temperature close to the boiling temperature.