Plasma initiation of vacuum arcs on a metal surface partially covered with a dielectric film

Excitation of vacuum arcs in the interaction of a plasma flow with a metal surface partially covered with a dielectric film is investigated experimentally and theoretically. A new phenomenon - the excitation of microscale electrical breakdowns (microplasma discharges) at the boundary between the free metal surface and the area covered with the film - is discovered. Microplasma discharges at the edge of the dielectric film are initiated by a strong electric field (ges1 MV/cm) that arises between the free metal surface and the outer surface of the film in the interaction with the plasma flow.