A new vacuum controlled switch for high-power-pulse generation and crowbar service

A new switching device is described which is capable of operating at several kilovolts and hundreds of amperes at pulse repetition frequencies of at least several tens of pulses per second and at pulse widths continuously adjustable from a few microseconds to dc. The device, which is expected to have an ultimate voltage capability of at least several tens of kilvolts, employs a vacuum arc as an emission source and utilizes an axial magnetic field in a cylindrical geometry for current control. The voltage drop across the switch is a function of the cathode material and is typically from 10 to 20 volts. In the case of a zinc cathode the drop is approximately 15 volts. Preliminary studies of the turn-on anc turn-off times during pulsed operation have shown that these times can be made shorter than 2 microseconds with little difficulty. A qualitative description of the operation of the device is given which is based on published information and on imformation obtained at Cornell Aeronautical Laboratory during several years of studies of vacuum arcs.