Raman instability of the Stokersquo;s component of the scattered electromagnetic wave has been investigated analytically in annhyphen;type nondegenerate piezoelectric semiconductor plasma subjected to a large longitudinal magnetostatic field. The general dispersion relation has been obtained following the coupled mode theory and considering that the scattering is due to both the molecular vibrations produced due to the pump wave at a frequency equal to that of the transverse optical phonons and the electron plasma wave. The dispersion relation has been solved for both cases of scattered electromagnetic waves (i.e., in the cases of lefthyphen;hand and righthyphen;hand circularly polarized waves). The threshold value of the pump amplitude necessary for the onset of instability and the growth rate of the unstable mode well above the threshold have been obtained analytically for both the modes. The relevant experiment has not been reported. It is observed that with the increase in the longitudinal magnetostatic field, the threshold value of the pump amplitude increases while the growth rate decreases in both cases. Numerical estimates have been made fornhyphen;type InSb at 77 K irradiated with a pulsed 10.6hyphen;mgr;m CO2laser to obtain the necessary electric field. The analytical as well as numerical results have been compared with those of Ghosh lsqb;J. Appl. Phys.52, 4667 (1981)rsqb; while studying the Brillouin instability in longitudianally magnetizednhyphen;type semiconductors.
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