A COMBINED PARAMETRIC AND CONVERSION MECHANISM FOR UPSHIFTED STIMULATED ELECTROMAGNETIC EMISSIONS

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