Hybrid precorrected FFT - Poisson solver method for the magnetostatic field in finite element micromagnetic modeling

A hybrid integral evaluation – differential equation approach is introduced for the computation of the magnetostatic fields in finite element method based micromagnetic solvers. The approach calculates the magnetostatic field at the boundary of the computational domain or any additional surfaces by direct superposition via a fast approach, such as precorrected fast Fourier transform and uses this surface values to formulate a Poisson equation with Dirichlet boundary conditions to compute the field in the bulk of the structure. The benefits of this hybrid approach are a significant reduction of the sparse matrices used in the accurate integral evaluation with the associated memory reduction as well as the ability to subdivide the problem into a set of smaller problems for parallelization.