Influence of metal vapour release on pseudospark switch performance

Summary form only given. The pseudospark discharge is a low pressure (10-100 Pa of hydrogen or helium) gas discharge in a coaxial electrode geometry. Both, cathode and anode are built as hollow electrodes and have a central bore. For the use as a fast closing switch at least 10/sup 9/ electrons have to be injected into the hollow cathode to ignite the discharge with low timing jitter. Within some tens of nanoseconds the discharge runs through different modes and the switch impedance drops to very low values. A typical pseudospark switch (3 mm electrode distance, 3 mm electrode holes, 4 mm electrode thickness) was run in a circuit with low current rise (10/sup 9/ A/s) to prolong the discharge phases. Different investigations (spectrally resolved fast shutter photography and photo multiplier measurements, determination of the electron beam passing into the hollow anode by a Faraday cup, measurement of the forward voltage drop FVD by two high voltage probes) were performed. Results of these measurements are compared to quantitative measurements of the metal vapour density by laser induced fluorescence. Possible mechanisms of the different discharge phases are discussed.