Combined experimental and theoretical study of constriction threshold of large-gap AMF vacuum arcs

High-speed videos of high current large-gap drawn vacuum arcs are compared to 3D ab-initio plasma simulations for different short circuit currents and external axial magnetic fields. In the experiments, defined arc modes and constriction thresholds are observed in quantitative agreement with the simulations. For the diffuse mode at high currents pronounced ring structures in the energy flux to the anode are well reproduced by the theoretical model. A detailed quantitative theoretical understanding of high current large-gap vacuum arcs is concluded.