Hydrodynamical field fluctuations in a non-equilibrium quasi-stationary state due to a temperature gradient

Within the general theory of hydrodynamical field fluctuations in a system at non-equilibrium due to a temperature gradient, the problem of light scattering on fluctuations in number density is discussed. The effect of the gradient as well as fluctuations in sound velocity and heat conductivity on the Rayleigh-Brillouin spectrum is analyzed. The presence of the temperature gradient and fluctuations modifies the scattered-light spectrum leading to asymmetry in the heights of the Brillouin lines.