Plasma Cathode For High Current Density Plasma Erosion Opening And Closing Switches

We have constructed a plasma cathode that produces a uniformly diffuse discharge in vacuum (5 x 10/sup -5/ torr), with a current density of more than 60 A/cm/sup 2/. The plasma cathode consists of a number of plasma sources integrated to the electrode body, in such a way that when they are triggered the discharge volume is filled with a plasma that allows the transit of high current densities through the gap. Analysis of the preliminary test results shows a peak current density which is only limited by the conditions of the external circuit. The plasma cathode can be configured in a flat, radial or even a non-spherical geometry to focus the plasma ejected from each source. Voltage and current traces showing the behavior of the system are shown as well as the system set-up. Preliminary calculations show that the total current through the gap is not space-charge limited and that current conduction is through the bulk of the plasma. The device is ideal for plasma erosion opening switches or high current repetitive vacuum switches.