On parametric excitation of plasma oscillations in n-InSb

The parametric instability of an n-InSb electron plasma in the field of a strong circularly polarized electromagnetic wave is considered. In case ωsub(0)<2ωsub(p)/√epsilonsub(0) (ω0 is the frequency of the pumping wave, ωsub(p) is the plasma frequency) there occurs an instability of the longitudinal oscillations of the plasma with a frequency of ω<<ω0 and of transverse oscillations with a frequency close to ω0. This instability is due to the non-standard character of the dispersion law epsilon(p). At ωsub(0)>ωsub(p)/√epsilonsub(0) two more regions of instability of longitudinal plasma oscillations appear, with a frequency of the order of ωsub(p)/epsilonsub(0) and of transverse ones with frequencies of ωsub(0)+-ωsub(p)/√epsilonsub(0)