Influences of Gas Gap Parameters on the Voltage Rise Time of Pulse Modulator

The voltage rise times of vacuum diode were theoretically and experimentally studied using a high pulse power modulator.The modulator used in the experiment was a single coaxial water dielectric transmission line.The voltage rise times of vacuum diode used as the load of the pulse modulator were studied under different conditions.First,the rise time was compared when the gas switch had the same gas pressure and different gas gap distance;Second,the rise time was studied when the switch had different gas pressures(0.5MPa,1MPa,1.5MPa,2MPa)with the same gas gap distance.Finally,under the same breakdown voltage of gas spark switch,the rise time of different gases such as H2,N2,SF6 used respectively as working dielectric of the gas switch was compared.The experimental results show that the voltage rise time of vacuum diode can be reduced when the gas pressure increased or the gas gap distance decreased.Using hydrogen as working dielectric of the gas switch can reduce the voltage rise time of vacuum diode compared with N2,SF6.And nitrogen switch has the faster rise time compared with SF6.The experimental results are in agreement with theoretical analyses.