PARAMETRIC-EXCITATION OF A COUPLED UPPER HYBRID-ACOUSTIC WAVE AND AN EXTRAORDINARY WAVE IN A PIEZOELECTRIC SEMICONDUCTOR PLASMA

In the present work we have considered a parametric interaction in a p iezoelectric semiconductor plasma. The three waves involved in the par ametric excitation are the pump wave, a coupled upper hybrid-acoustic wave and an extraordinary wave. An analytical expression for the growt h of the unstable mode is derived and an expression for the threshold electric field for the onset of the instability is also derived. We ha ve numerically investigated the dependence of the threshold electric f ield for different values of the background parameters for a typical p iezoelectric semiconductor (InSb) and have given a numerical estimatio n of the growth rate.