Breakdown phenomena in ultra-fast plasma closing switches

An experimental investigation into the rate of voltage collapse in plasma closing switches has been undertaken. A transmission line test switch, incorporating a radial/conical topology to minimize wave reflections, has been used for this investigation. The results described were obtained from experiments using hydrogen, helium, nitrogen, and SF/sub 6/. The results show that there is a distinct change in breakdown behavior as the pressure increases. At the lowest tested pressures, there is a rapid voltage collapse phase. This phase reduces at intermediate pressures before recovering at higher pressures. This transition from low-pressure behavior to high-pressure behavior occurred in all the tested gases, although the transition pressure values were dependent on the gas type.