EMISSION OF PLASMA CYCLOTRON WAVES IN PLASMA-FILLED BACKWARD-WAVE OSCILLATORS

It is found through computer simulations of plasma-filled backward-wave oscillators that within a certain range of magnetic field the growth rate of beam-plasma cyclotron interaction is significantly larger than the conventional backward-wave oscillation. This slow plasma cyclotron wave is emitted from plasmas only if it also satisfies the dispersion relation of a rippled-wall waveguide which couples the slow wave to fast wave. This observation may be employed to interpret previous experiments which displayed a strong dependence of output power on the magnetic field. © 1990 The American Physical Society.