Cyclotron harmonic maser

A cyclotron resonance maser configuration is proposed which may allow operation at the higher cyclotron harmonics. Instability growth rates at the higher harmonics are shown to be significant when coupling between transversely- and longitudinally-polarized waves occurs at the electron beam boundary, for radiation propagating across the static magnetic field. With experimental parameters well within practical ranges, oscillation in a single device, tunable from about 100 to 1000 GHz, is shown to be possible.