Peculiarities of Operation of a Relativistic Backward-Wave Oscillator Driven by an External Electromagnetic Signal

We study operation of a relativistic backward-wave oscillator driven by an external electromagnetic signal. Such operation regimes as hard excitation of self-oscillations and amplification of the external signal are implemented experimentally. The conditions for possible synchronization of the relativistic backward-wave oscillator by an external signal is discussed. The possibility of accelerating the onset of oscillations by the action of an external signal is confirmed experimentally. The conditions of realization of the amplification regime and the main effects, which limit the amplification coefficient, are determined. The obtained results can be used to optimize the parameters of generators and amplifiers based on relativistic backward-wave oscillators.