H− generation using an externally applied prepulse

Experiments on H⁻ generation in a high-power, pulsed, magnetically insulated diode are described. The ERG accelerator of the P.N. Lebedev Physical Institute in single line configuration was used with voltages up to 600 kV and pulse duration of 200 ns. To create cathode plasma, the surface discharge on dielectric was initiated by an externally applied prepulse, which was one 1.5 μs period of a sinusoid with up to 100 kV amplitude. The circuit allows to work with a prepulse of easily varied amplitude and duration, either with Blumlein or single forming line as the source of the main high-voltage pulse. Negative hydrogen ion current densities up to 10 A/cm² were recorded using trace detecting by CR-39.