Modification of Electron Cyclotron Maser Operation by Application of an External Signal.
NAVAL RESEARCH LAB WASHINGTON DC
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Operation of the electron cyclotron resonance maser ECRM when subjected to an external rf signal is studied. The signal is introduced both by direct injection through a coupling hole in the oscillator and by modulating the electron beam in separate cavities, upstream of the oscillator. Experiments using both one and two pre bunching cavities are reported. It is found that the gyromonotron, a specific embodiment of the ECRM, can be phase locked by premodulating the electron beam. In this case, the required drive power levels are more than 15 dB below that predicated by Adlers widely applicable theory for single-cavity oscillators. In addition, the same method allows oscillator phase-locked systems, significant reduction of frequency and amplitude noise is observed within the locking band. In signal of a power level 65 dB below that of the oscillator. The general amplitude and frequency response of the ECRM to an applied external signal is also investigated. Three distinct regions of qualitatively different behavior are noted soft excitation, which is free, self excited oscillation hard excitation, where the oscillation requires an external impulse for start up and amplifier, in which the output power level and frequency are linearly related to the drive in the small regime. Keywords Gyroklystron Primed oscillator Gyrotron Phased locked oscillator.
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