A DC to AC radiation converter based on plasma ionization

Summary form only given, as follows. We describe programs on a new class of high power radiation source. Rather than create electromagnetic fields, the present scheme frequency upshifts an existing static field (/spl omega/=0, k=k/sub 0/) by temporally varying the dielectric properties of a medium (i.e., ionizing a gas). An array of alternating capacitors is charged to a large voltage to produce a static electric field of the form E/spl sim/(E/sub 0/ sin k/sub 0/ Z) y. When the region between the capacitors is filled with a low density working gas and ionized by a short-pulse laser, a phased discharge current generates a radiation pulse following behind the ionizing laser. The frequency of the radiation generated scales as f=8 GHz (n/sub 0//10/sup 12/ cm/sup -3/) (1 cm/k/sub o/), where n/sub 0/ is the plasma density. The output frequency, pulse duration, bandwidth, arbitrary chirp, etc. can be controlled by varying the gas pressure and/or capacitor spacing. Output power is determined by the bias voltage, and high powers are in principal possible by using pulsed biases. At USC/UCLA proof-of-principle experiments are underway to test the predicted characteristics of this alternative source of high-power microwaves. Preliminary results are presented.