Mechanism of runaway electron generation in a plate-plate atmospheric air gap under nanosecond pulse voltage

Classical discharge theory (Townsend and streamer theory) has limitations in explaining nanosecond pulsed gas discharge. In recent years, the research on based high-energy runaway electrons attracted extensive attention. But so far, there have been few studies of generation mechanism atmospheric-pressure-air plate-to-plate discharge, which seriously hinders application development pulse plasma. this paper, a one-dimensional implicit particle-in-cell/Monte Carlo collision (PIC/MCC) model is developed to investigate electron breakdown 1 mm-long gap between plate electrode driven by negative voltage with an amplitude 20 kV. The results show that under influence space charge dynamic behavior, electric field enhancement region appears electrode, can satisfy criteria behaves mode. addition, it also observed pre-ionization effect front channel cause secondary avalanches. As avalanche continues converge, guided accelerated, eventually leading air gap. This study further reveals plate-plate expands basic opens up new opportunities for