Stability of diffusion fronts of magnetic particles in porous media (Hele-Shaw cell) under the action of external magnetic field

A. Cebers

Institute of Physics, Latvian Academy of Sciences, Salaspils-1, LV-2169, Latvia

Abstract
On the basis of the Darcy equation with account for ponderomotive magnetic forces the fingering instability of the magnetic particle diffusion front is considered. It is shown that there exists threshold value of the magnetic field strength depending on the diffusion coefficient of the magnetic particles above which vortice-like fluid motion at diffusion front arises. In the limit of the steplike magnetic particle concentration distribution the critical value of the magnetic field strength is calculated exactly. Smearing of the magnetic particle concentration distribution due to the thermal diffusion leads to the increase of the critical magnetic field strength and shift of the most fast growing mode to the larger wavelengths. Existing experimental results relevant to the approach considered in the present paper are pointed out. Figs 4, Refs 14.