A COMBINED PARAMETRIC AND CONVERSION MECHANISM FOR UPSHIFTED STIMULATED ELECTROMAGNETIC EMISSIONS

We study the combined process of a three-wave parametric decay of an oscillating electric pump field into an electron Bernstein and a lower hybrid wave, and a conversion of the pump wave off slowly growing field aligned irregularities into an upper hybrid wave which merges with the lower hybrid wave. It is found that slowly growing, upshifted stimulated electromagnetic emissions, observed experimentally for pump frequencies-slightly above electron cyclotron harmonics, are well explained within this model. In the radiation spectrum there is a lower cutoff frequency which increases linearly with the cyclotron harmonic.