A low-frequency crossed-field amplifier for experimental investigations of electron-radio frequency wave interactions

A low-frequency (100-200 MHz) crossed-field amplifier has been designed and constructed for the purpose of studying electron-radio frequency wave interactions. The device has been designed to allow in situ diagnostic probe measurements of the interaction region during the amplification process. Details of the design and operating parameters in the beam-injected mode are described. A maximum gain of 7 dB for a circuit of short electrical length (six slow wave wavelengths) has been obtained. Measurements of the local radio-frequency field during amplification, of the electron density profile, and of the electron plasma current-voltage characteristics in the interaction region demonstrate the use of probes to diagnose the electron plasma in a crossed-field amplifier configuration. These experiments will provide a basis for investigations of noise generation and nonlinear interactions in the more complex emitting-sole, reentrant crossed-field amplifier.<
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