Thermal convection in a ferrofluid supported by thermodiffusion

Convective motion has been investigated in a ferrofluid layer heated from below. In contrast to normal experiments on thermal convection in fluids, the focus of this investigation was devoted to the destabilizing effect of the density redistribution in the fluid forced by thermal diffusion of the magnetic particles relative to the carrier liquid. It could be shown that the fluid layer is destabilized at a temperature difference well below the critical limit for a one-component fluid. It was found that the convective flow is stable in time and the measured convection amplitude could be fitted with a theory given by Hollinger et al. (Phys. Rev. E 57 (1997) 4).