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 el ectrodes is studied. Results of an experiment based on a design which incor porates the capacitor electrodes into an X band waveguide are presented. Th e waveguided design effectively couples nearly three orders of magnitude mo re power into the output than the previously unguided designs. Linear theor y 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 finit e output pulse duration. (C) 2001 American Institute of Physics.