CONVECTION DRIVEN BY FORCED DIFFUSION IN MAGNETIC FLUIDS

A convective flow in a suspension of magnetic particles driven by an interaction between a magnetic field gradient and a concentration gradient of the magnetic component of the fluid has been investigated. The concentration gradient itself is produced by a diffusion of the particles in the field gradient. It causes the demixing of the fluid. In the nonequilibrium states of this process a concentration gradient of the magnetic particles antiparallel to the field gradient establishes. The interaction between these two gradients gives rise to the convective flow. Experiments have been performed to prove the existence of this convection and to investigate its onset. In addition, a model has been formulated based on a time-dependent dimensionless parameter to interpret the experimental data.