Parametric excitation of lower hybrid waves by helicon waves in magnetoactive semiconductors

Abstract

A theoretical investigation has been done on the parametric excitation of the electrostatic lower hybrid wave when an electromagnetic helicon wave propagates in a magnetoactive semiconductor. Fluid equations of homogeneous plasmas have been employed to find the nonlinear response of electrons. The low frequency nonlinearity arises through the ponderomotive force on electrons, whereas the high frequency nonlinearity arises through the current density associated with the scattered helicon wave. For the typical plasma parameters in n-type indium antimonide and for the considerable power density (∼7.6 kW cm−2) of the incident helicon wave, the growth rate of the parametric instability turns out to be quite large (∼108 rad s−1). The presence of the linear damping of the decay waves in the semiconductor plasma reduces the growth rate of the instability by two orders of magnitude.