K. N. Ovchinnikov

Reflection and absorption of HF radiation by a turbulent plasma

Reflection and absorption of a linearly polarized wave by a plasma with developed ion-acoustic turbulence is studied. The dependences of the absorption coefficient and Stokes parameters of the reflected elliptically polarized wave on the anisotropic effective frequency of electron collisions are established.

Interaction of electromagnetic radiation with a plasma with fully developed ion acoustic turbulence

A study is made of the characteristic features of the reflection and absorption of a monochromatic wave by a plasma with axisymmetric ion acoustic turbulence over a broad frequency range. The absorption anisotropy and the related conversion of an incident, linearly polarized wave into a reflected, elliptically polarized wave are described. The absorption coefficient and the difference in the phase shifts occurring in the reflection of different field components are obtained as explicit functions of the turbulent plasma parameters.

Action of an electromagnetic pulse on a plasma with a high level of ion-acoustic turbulence. Field diffusion and subdiffusion

Specific features of the interaction of a relatively weak electromagnetic pulse with a nonisothermal current-carrying plasma in which the electron drift velocity is much higher than the ion-acoustic velocity, but lower than the electron thermal velocity, are studied. If the state of the plasma with ion-acoustic turbulence does not change during the pulse action, the field penetrates into the plasma in the ordinary diffusion regime, but the diffusion coefficient in this case is inversely proportional to the anomalous conductivity. If, during the pulse action, the particle temperatures and the current-driving field change due to turbulent heating, the field penetrates into the plasma in the subdiffusion regime. It is shown how the presence of subdiffusion can be detected by measuring the reflected field.

Stimulated Brillouin scattering in a dusty plasma

A kinetic description is developed for stimulated Brillouin scattering (SBS) in a dusty plasma with negatively charged dust grains. The threshold for SBS and the width of its spectral line are determined in the limits of weak and strong damping of the dust ion acoustic waves involved into the scattering process. For different mechanisms of the dissipation of dust ion acoustic waves, the threshold for SBS and the width of its spectral line are obtained as functions of the dust grain charge and the dust number density.

Penetration of probe field in heated plasma

Dependences of the effective penetration depth of probe pulse field in current-carrying plasma with time-dependent temperatures of particles are determined. It is shown that the field penetration in fully and weakly ionized plasmas takes place in the subdiffusion and superdiffusion regimes, respectively.

Anomalous penetration of an electromagnetic field into a nonisothermal plasma with two species of ions

It is shown that a change in the ion composition of a nonisothermal plasma is accompanied by nontrivial changes in the effective penetration depth of a strong quasi-stationary electromagnetic field generating ion-acoustic instability.

Nonlinear spectral properties of stimulated Brillouin scattering in plasma

New phenomena in which the stimulated Brillouin scattering (SBS) changes the number and magnitude of frequency shifts in a plasma upon a nonlinear increase in the pumping field intensity are discovered. It is found that the SBS becomes forbidden and then allowed again (upon a subsequent increase in the pumping intensity).