Fluctuations in a Nonequilibrium Steady State: Light Scattering from a Thermal Gradient.
Abstract
Near equilibrium fluctuation theory is extended into the nonequilibrium regime through the use of the postulate of local equilibrium, and the resulting nonequilibrium fluctuation theory is applied to a hydrodynamic system in which a steady state thermal gradient is presented. This approach to nonequilibrium fluctuation theory is applied in an experimentally testable context to light scattering from water. In particular, the effects of the temperature dependence of the hydrodynamic transport coefficients upon the intensity of Rayleigh scattering are investigated. This calculation is accomplished by using Fourier series to reduce the hydrodynamic equations to matrix form. The resulting matrix equation is solved for the mass density fluctuations, and the mass density autocorrelation function is then computed. The connection between the mass density autocorrelation function and the structure function describing the scattered light intensity is established, and the Rayleigh intensity is computed. The result of this calculation indicates that the presence of a thermal gradient induces an enhancement of the Rayleigh intensity which may be a substantial fraction of the corresponding equilibrium intensity.
 Publication:

Ph.D. Thesis
 Pub Date:
 1983
 Bibcode:
 1983PhDT........89B
 Keywords:

 Physics: General