Multiscale modelling of micromagnetic processes using the linearised Landau-Lifshitz equation

Sammanfattning: The problem with introducing multiscale domains when modelling mi- cromagnetic processes is that some phenomena cannot be resolved in the coarser mesh. When using a structured grid, with an interface between the meshes, these phenomena reflect back into the fine mesh as a non- physical result of the discretization. Landau-Lifshitz is solved by using a new, higher order, energy con- serving, finite difference, method. The particular issue of reflections is handled by weakly damping the high frequencies of spin waves, travelling across an interface, using penalty terms close to the interface. A couple of ways of imposing these penalty terms are implemented, which results in the damping of high frequencies, and creates unwanted reflections from the low frequencies that travel across the interface. The result is pre- sented and other ways of implementing the penalty terms at the interface is discussed.