3D simulation of the interaction between double copper cathode spot jets in vacuum arc

The mixing process of the cathodic jets is an important connection between the metal surface and the plasma arc column, which helps to understand the diffusion mechanism of the vacuum arc and guides the vacuum switch design. The interaction process of double cathode jets is simulated using a 3D magnetohydrodynamic method. This study analyzes the evolution of plasma parameters as the double cathode jets transition from a separated state to a mixed state. The results indicate that a mixed single-peaked jet ultimately forms at the exit when the double cathode jets are present at the inlet of the cathode surface. The transition from the separated state to the mixed state occurs further away from the cathode surface as the inlet current density of the jets increases from 3 to 5 × 109 A/m2. Additionally, the asymmetry in the current density of the double cathode jets causes the peaks of the mixed single-peak current density and ion temperature to be skewed toward the direction of the lower inlet current density. In cases where the inlet current direction is asymmetric, the peaks shift toward the direction where the inlet current is perpendicular to the cathode surface. Furthermore, the outward expansion acceleration trend of the plasma aligns well with the results from single-jet numerical simulations.