The pseudospark discharge offers the possibility of producing electron beams which are very attractive for use in high-power microwave generation. A pseudospark-based Cherenkov maser amplifier is currently under development at Strathclyde University. The electron beam source for this maser is a multi-gap pseudospark discharge. Preliminary results from recent Cherenkov maser experiments and a comparison with a numerical simulation are presented. A microwave pulse of 100 ns duration and approximately 10 kW peak power was generated by a 80 kV, 20 A beam passed through an alumina-lined waveguide when the interaction was allowed to start up from noise, which appeared to originate from the pseudospark discharge. Simulations agree well with the experimental results when a beam energy spread of 1.5% is assumed.

A pseudospark-sourced electron beam has two phases, an initial hollow cathode phase (HCP) beam followed by a conductive phase (CP) beam. The beam brightness was measured by a field-free collimator to be 10 9 and 10 11 Am À2 rad À2 for HCP beam and CP beam, respectively. The initial HCP beam from an eight-gap pseudospark discharge was applied in a Cherenkov interaction between the electron beam and the TM 01 mode of a 60-cm long alumina-lined waveguide. While the CP beam from a three-gap pseudospark discharge chamber was propagated and post-accelerated from about 200 V to more than 40 kV.