Pulse propagation effects in a cyclotron resonance maser amplifier

An analysis is presented of a cyclotron resonance maser amplifier operating with electron pulses. The electrons are resonant at two frequencies of the same waveguide mode. We consider both a single resonant frequency interaction and also a coupled two resonant frequency interaction. It is shown that, in general, the interaction with both resonant frequencies must be taken into account. The analysis includes propagation effects due to the difference between the axial velocity of the electrons and the group velocities of the radiation fields. Both linear and numerical solutions to the equations are given, and superradiant emission is demonstrated where the radiated power scales as the square of the electron pulse current. Two methods of low-frequency suppression are presented allowing the high-frequency emission to dominate. These results may have important consequences for the generation of short pulses of high-frequency, high-power microwave radiation. [S1063-651X(99)01001-6].