Methods of Calculation the Magnetic Forces Acting on Particles in Magnetic Fluids

In a nonuniform magnetic field a force acts on ferromagnetic particles, which results from the mutual reaction between the induced magnetic moment in a particle and applied external magnetic field. This phenomenon is named magneto-phoresis, and is used in a various commercial and industrial processes for, among others, for separation of solid magnetic particles suspended in fluids. There are two methods for calculating forces acting on a magnetic particle placed in a magnetic liquid: the first is an equivalent dipole method and the second method is based on Maxwell's stress tensor. Both of these forces can be used in hyperthermia based on magnetic fluids supplied to the patient's body via blood. These forces should cause the placement of ferromagnetic microscopic particles in an adequate place in the patient's body, and then they should be used to produce a heat that interacts with the tumor. These two methods are compared in terms of accuracy and parameters that affect their accuracy. This article will discuss two mentioned methods for calculating forces acting on a particle in a magnetic fluid.