On the irreversibility of fluctuations

Interrelationship of classical and quantum fluctuations is discussed. With energy dissipation being taken into account, fluctuations are shown to be irreversible even in the case of classical systems. An analogy to Kubo relation for classical fluctuations is derived. Fluctuations in both equilibrium and nonequilibrium (though stationary) states of the system are considered.Обговорюється взаємозв’язок між класичними та квантовими флюктуаціями. Вказано на незворотність (навіть у випадку класичних систем) флюктуацій за наявності дисипації енергії. Одержано аналог співвідношення Кубо для класичних флюктуацій. Розглянуто флюктуації як у рівноважних, так і в нерівноважних (але стаціонарних) станах системи

Rotational kinetics of absorbing dust grains in neutral gas

We study the rotational and translational kinetics of massive particulates (dust grains) absorbing the ambient gas. Equations for microscopic phase densities are deduced resulting in the Fokker-Planck equation for the dust component. It is shown that although there is no stationary distribution, the translational and rotational temperatures of dust tend to certain values, which differ from the temperature of the ambient gas. The influence of the inner structure of grains on rotational kinetics is also discussed.Comment: REVTEX4, 20 pages, 2 figure

Wave Mixing and Electromagnetic Wave Scattering in Plasmas

Kinetic and fluid treatments of nonlinear wave interactions (wave mixing and electromagnetic wave scattering) in plasmas are considered and the difference between the two approaches is discussed. Solving the kinetic equation by the method of moments makes it possible to substantiate the validity and find the applicability range of the fluid approach to the study of nonlinear plasma processes. In particular, the detailed study of nonlinear processes in a plasma with external magnetic fields is performed. In the case of wave transformation, when mixed waves satisfy linear wave equations, both fluid and kinetic approaches yield similar expressions for the inducing current. In the case of electromagnetic wave scattering by thermal fluctuations, the results of the fluid and kinetic approaches are in accordance only in the limiting case of cold plasmas when thermal effects may be completely disregarded (these are thermal corrections to the wave dispersion equation and the additional Langevin source in the constitutive equation for fluctuations). Different expressions for the inducing current, obtained from various versions of hydrodynamic equations, reduce to the same form in the cold plasma limiting case

NONLINEAR WAVE INTERACTION AND CRITICAL FLUCTUATIONS IN PLASMAS

No abstract availabl

Kinetic description of electromagnetic fluctuations in a plasma with fluid-like random motions

The kinetic theory of electromagnetic fluctuations is worked out for turbulent plasmas with given statistical properties of large-scale turbulent motions. Correlation functions of electron number density fluctuations in such a plasma are calculated. Numerical analysis of fluctuation spectra is performed for a turbulent plasma with diffusive motion of volume elements