Fluctuations and scattering of transverse electromagnetic waves by density fluctuations in a magnetized plasma in the presence of parametric decay of the pump wave are investigated. The spectral density of electron-density fluctuations is calculated. It is shown that the differential scattering cross-section has sharp maxima at the ion-acoustic and lower-hybrid frequencies when parametric decay of the lower-hybrid pump wave occurs. We note that scattering at the ion-acoustic frequency is dominant. When the pump-wave amplitude tends to the threshold strength of the electric field the scattering cross-section increases anomalously, i.e. there is critical opalescence.

The influence of an r.f. pump wave on the spectral electric field fluctuation density and the value of the electromagnetic wave energy density, which is absorbed in the presence of parametric instabilities, is investigated. The r.f. fie!d power which is absorbed in the plasma is estimated near the threshold of the decay instability. It is shown that the absorbed power increases anomalously as In(E:,,JE; -1) for the decay of pump wave into lower hybrid and ion-acoustic waves and as (E:h.z/Ei -1 ) -' l 2 for the decay of pump wave into lower hybrid wave and ion quasimode (Eih.l and Eih.2 are the threshold electric field strength relatively to the excitation of the instabilities which are under consideration and Eo is the pump field strength).

A magnetized plasma in the presence of a high-power electromagnetic pump wave is considered. Supposing that the parametric instabilities of this system are saturated by the scattering of the charged particles on the turbulent fluctuations, we derive the effective collision frequency for the case where the upper-hybrid pump excites ion-sound and ion-cyclotron waves.

The scattering of electromagnetic waves by density fluctuations in a magnetized plasma in the presence of an external pump field is investigated. The pump wave is supposed to decay into a lower-hybrid and an ion-cyclotron wave in a plasma with ion-temperature anisotropy.The cross-section obtained for the scattering of electromagnetic waves by turbulent fluctuations above threshold for the decay processes is found to be comparitively sensitive to the ion temperature anisotropy.

No abstract