Numerical solution of Fokker-Planck equation for single domain particles

The Fokker-Planck equation proposed by Brown to describe the evolution of the probability distribution density of the orientation of the magnetic moment of a single-domain particle is usually solved by expanding the unknown function in a series of spherical harmonics. In this paper, we use a different method to solve the Fokker-Planck equation, namely, the finite element method. We describe the procedure for constructing a triangular grid on the surface of a sphere and give formulas for calculating the coefficients of the equations for the probability density values at the grid nodes. As an example, the results of calculating the dynamic magnetic hysteresis for particles with cubic anisotropy are demonstrated.