Statistical theory for cluster phenomena of magnetic fluids.

Abstract

Magnetic fluids have certain unique properties which are very important in physics as well as in engineering. Recently, it has been reported that ferromagnetic particles form clusters even in a weak magnetic field. No one has analyzed the cluster phenomena in detail. In the present paper, a new statistical equation is derived by considering the cluster phenomena using a transport theorem in statistical mechanics. The basic concept is an extension of the Bolzmann equation for plasma which is applied as a model of the combination of ferromagnetic particles in the collision process and dispersion of cluster by the phase transition from a microscopic viewpoint. By the present method, we can calculate the increment of apparent viscosity under the contribution of cluster and the critical magnetic field where clustering appears.