Influence of external ultra high axial pulsed magnetic fields on high current vacuum arcs

Numerical simulation of high-current vacuum arcs in presence of magnetic fields has been the subject of several investigations. With increasing axial magnetic field, the multiple arc mode region extends to higher arc currents. This is used in vacuum interrupters to keep the arc in diffused mode. Because of the very fast recovery of the vacuum arcs burning in diffused mode, the fault currents can be easily interrupted. The magnetic field amplitudes considered in the preceding studies are all less than hundreds of mT. In this paper, the interaction of the vacuum arcs with much more intense magnetic fields of several Teslas are considered. For this purpose, the Magnetohydrodynamics equations describing the behavior of the vacuum arc in high current mode are simulated in presence of a very intense pulsed magnetic field generated by a high current pulsed power source. The results indicate that the diffuse mode can be extended to much higher current amplitudes; this can be used to improve the interruption capability of vacuum interrupters.