Thermally induced nonequilibrium fluctuations in fluids: gravity and finite-size effects
Jan V. Sengers, Institute for Physical Science and Technology, University of Maryland

This lecture will be concerned with thermal fluctuations in fluids in the presence of a temperature gradient. Nonequilibrium fluctuating hydrodynamics has shown that these fluctuations are always spatially long ranged due to mode-coupling effects induced by the temperature gradient. The intensity of the nonequilibrium fluctuations is greatly enhanced compared to those in equilibrium and exhibits a dramatic dependence on the wavelength at all length scales in the system. At small wavelengths the intensity of the nonequilibrium fluctuations increases with the fourth power of the wavelength. At larger wavelengths the fluctuations become affected by gravity and finite-size effects. Currently available experimental information will be reviewed and suggestions for further research will be presented.