High-peak power K/sub a/-band gyrotron oscillator experiments with slotted and unslotted cavities

A K/sub a/-band gyrotron oscillator powered by a compact pulseline accelerator has been operated using oscillator cavities with and without axial slots. The oscillator was operated at high voltage ( approximately 900 keV) and high current ( approximately 500 A) in the approximate frequency range of 20-50 GHz. The use of axial slots has been shown to suppress low-starting-current whispering-gallery modes, in particular, modes of the TE/sub m2/ type, allowing stable operation in a linearly polarized TE/sub 13/ mode. A peak power of 35 MW has been observed at 6% efficiency.<
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