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Magnetic Effects on the Diffusion of Ferromagnetic Colloidal Particles Dispersed in a Current-Carrying Fluid Medium
Phys. Rev. 145, 64 – Published 6 May, 1966
DOI: https://doi.org/10.1103/PhysRev.145.64
Abstract
A theoretical investigation is made of the magnetic effects on the diffusion of ferromagnetic colloidal particles dispersed in a current-carrying fluid medium. Specifically, the following problem is analyzed: Consider an infinitely long circular cylindrical metallic-based ferrofluid confined at its cylindrical surface by an impermeable wall. The initial distribution of dispersed ferromagnetic particles is cylindrically symmetric but otherwise arbitrary depending only on the radial distance from the axis. At time , a uniform electric current is made to flow through the ferrofluid in the axial direction. In the presence of the magnetic field associated with the current flow, an analytical solution for the subsequent spatial and temporal behavior of the particle distribution function was obtained and then shown to reduce to the corresponding classical diffusion problem in the absence of the magnetic force. The effect of the magnetic force on the relaxation process and on the equilibrium distribution itself was then examined numerically for the specific case where the initial probability distribution function is a delta function located at the axis.
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