Kinematic simulation of dynamo action by a hybrid boundary-element/finite-volume method

A. Giesecke - F. Stefani - G. Gerbeth

Forschungszentrum Dresden-Rossendorf, Magnetohydrodynamics Department, POB 51 01 19, D-01314 Dresden, Germany

Abstract
The experimental realization of dynamo excitation as well as theoretical and numerical examinations of the induction equation have shown the relevance of boundary conditions for a self-sustaining dynamo. Within the interior of a field producing domain geometric constraints or varying material properties (e.g., electric conductivity of the container walls or localized high-permeability material) might also play a role. Combining a grid-based finite volume approach with the boundary element method in a hybrid FV-BEM scheme offers the flexibility of a local discretization with a stringent treatment of insulating magnetic boundary conditions in almost arbitrary geometries at comparatively low costs. Kinematic simulations of dynamo action generated by a well known prescribed mean flow demonstrate the reliability of the approach. Future examinations are intended to understand the behaviour of the VKS-dynamo experiment, where the field producing flow is driven by ferrous propellers and the induction effects of conductivity/permeability inhomogeneities might provide the required conditions for the measured dynamo characteristics. Tables 1, Figs 8, Refs 23.