Relativistic backward wave oscillators: Theory and experiment

The linear and nonlinear theory of backward-wave oscillators (BWOs) is developed taking into account reflection of the electromagnetic wave at the boundaries of the slow wave structure. The effects of finite duration and rise time of the electron beam pulse on device operation are discussed. A series of low-current experiments attempting to measure the start current has been conducted. The main challenge in the experiments was to achieve BWO operation over a wide range of electron beam energy and current. Since for a particular gun geometry the variation in the beam current is limited, the authors built a number of electron guns which made it possible to cover a broad range of beam parameters.<
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