Experimental study of the conversion of DC electric fields to microwave radiation by an ionization front created by successive discharges

Summary form only given, as follows. Most current high power microwave sources use either free electrons in the form of beams, or photon emission as the radiation source. Recently, however, a new method involving the direct conversion of DC electric fields to radiation fields has come to light. This new method uses an ionization front moving through a gas filled electrode array to produce an approximately sinusoidal static electric field. As the front passes an electrode pair, a burst of current, and thus a half cycle of radiation is produced. All the pulses then add coherently, giving a radiation field whose energy is derived directly from the DC electric field. Our experiment consists of an 3 band rectangular waveguide, in which several (/spl ges/5) pairs of oppositely placed holes are drilled. Through these holes are placed pairs of electrodes, between which a Marx capacitor bank is discharged. By adjusting the spacing of the electrodes, the first pair can be made to fire first. The resulting ultraviolet radiation from the spark preionizes the gas between the remaining electrodes, causing them to fire in sequence, and assuring that the microwave radiation pulses add coherently.