Nonequilibrium Concentration Fluctuations in Binary Liquid Systems Induced by the Soret Effect

Abstract. When a binary liquid system is brought into a stationary thermal nonequi-librium state by the imposition of a temperature gradient, the Soret effect induces long-range concentration fluctuations even in the absence of any convective instability. The physical origin of the nonequilibrium concentration fluctuations is elucidated and it is shown how the intensity of these concentration fluctuations can be derived from the linearized random Boussinesq equations. Relevant experimental information is also discussed.