a1 Institut für Theoretische Physik, Ruhr-Universität Bochum, 4630 Bochum 1, Federal Republic of Germany
It is shown that a finite-amplitude upper-hybrid wave can decay into a perpendicularly (to an external magnetic field B0 zˇ) propagating electrostatic lower-hybrid/ion-cyclotron wave and a left-handed circularly polarized (LHCP) electromagnetic wave (along B0) or an ordinary mode radiation (across B0). Nonlinear dispersion relations and the growth rates are obtained. It is suggested that the present nonlinear instability can be responsible for the enhanced narrow band radiation which is frequently observed in the Earth's magnetosphere.
(Received December 01 1983)
(Revised February 06 1984)
† Permanent address: Department of Physics, Quaid-i-Azam University, Islamabad, Pakistan.