A Microscopic Study of Before-Arc Process in Metal Vapor Plasma's Proximal Cathode Region. Part II the Influence of Macroscopic Parameters on the Proximal Cathode Region

Abstract

The moment of vacuum breaker contacts opening to arc creating process is an unbalanced gaseous breakdown process. This before-arc process is the foundation of studying arc process. The mechanism of the metal vapor arc is different from other gas medium and contains complex electrode process. The proximal cathode region is the important area for vacuum arc forming and it is affected by many factors. The influences of the different electrode separations, different secondary emission coefficient on electronic density, electronic temperature and electric potential, were analysed in this paper. The simulation results show that the change of electrode separations barely impacts the thickness of sheath and the decrease of electrode separations will lead to the decrease of electronic energy near the cathode sheath. The increase of secondary electron emission will increase charged particles energy, which is the important condition of forming cathode sheath.