In the present paper, parametric decay instability of an extraordinary electromagnetic (EM) wave into a high-frequency electron Bernstein wave and a low-frequency ion Bernstein wave is studied. The guiding center formalism is followed to obtain the coupling coefficients including kinetic effects. The momentum space integrals in the coupling coefficients are solved in the dipole approximation of the pump wave and in the limits, k⊥ρe<1 for electron Bernstein wave and k⊥ρi<1 for ion Bernstein wave. Analytical expressions for homogeneous growth rate and threshold are given explicitly. Applications of the present investigation are pointed out to ionospheric modification experiment and fusion plasmas.
Some of the parametric instabilities of an ordinary electromagnetic wave decaying into (i) a highfrequency upper hybrid wave and a low-frequency mixed-mode kinetic Alfven wave and (ii) an obliquely propagating ordinary scattered electromagnetic wave and a low-frequency electrostatic-ion Bernstein wave (stimulated Brillouin scattering) have been investigated. In channel (i), the partially electrostatic nature of the kinetic Alfven wave and the component of the low-frequency ponderomotive force along the direction of the external magnetic field lead to the dominant coupling. Explicit expressions for the growth rate and threshold power are given. It is found that, in the case of channel (ii), the homogeneous threshold power is lowest at the first harmonic of the low-frequency electrostatic-ion Bernstein wave. The relevance of the present investigation to fusion, ionospheric modification experiments, and space plasmas has been pointed out. For example, for fusion plasmas the convective threshold power for channel (i) is found to be approximately 20 kW/cm .
Parametric decay instability of the electron plasma wave into another electron plasma wave and an electrostatic whistler wave has been studied taking into account the full matrix elements. The relevance of this decay channel to the generation of whistler mode radiations in the Spacelab 2 experiment has been pointed out,
Abstract. The parametric decay instability of an extraordinary electromagnetic wave into an electron plasma wave and an electrostatic whistler wave has been studied. Explicit expressions for the homogeneous growth rate and threshold electric field have been presented for this instability. The relevance of the present parametric process has been pointed out to explain the generation of whistler mode radiations in the SL-2 experiment as well as in auroral magnetosphere (auroral hiss).
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