Parametric excitation of electromagnetic waves in a magnetized plasma

The parametric interaction of an upper-hybrid pump wave with kinetic Alfven and electromagnetic waves that propagate in parallel and perpendicular dir ections to the ambient magnetic field is investigated on the basis of two-f luid magnetohydrodynamics. A nonlinear dispersion relation describing three -wave interaction and instability growth rates are found. The theoretical r esults are used for the interpretation of satellite observations in the mag netospheric plasma. It is shown that as a result of the decay of an upper-h ybrid wave. electromagnetic waves propagating in both parallel and perpendi cular directions to the ambient magnetic field are generated. The instabili ty growth rate is much higher in the case of left-polarized electromagnetic wave generation than in the case of ordinary electromagnetic wave generati on. The nonlinear parametric processes studied here could also take place d uring powerful bursts on the Sun, and in the magnetosphere of Jupiter.