High power radiation from ionization fronts in a static electric field in a waveguide

The radiation produced when a relativistically moving plasma/gas boundary ~i.e., an ionization front! passes between alternatively biased capacitor electrodes is studied. Results of an experiment based on a design which incorporates the capacitor electrodes into an X band waveguide are presented. The waveguided design effectively couples nearly three orders of magnitude more power into the output than the previously unguided designs. Linear theory is extended to include the depletion of the laser energy as it propagates through the ionizable gas ~i.e., laser depletion!, and the effect of finite output pulse duration. © 2001 American Institute of Physics. @DOI: 10.1063/1.1377608#