An Earth Dynamo With Anisotropic Resistivity

A dynamo mechanism generating a self-sustaining dipole field as a result of the motion of a fluid with anisotropic resistivity is a possibility for the dynamo generating the dipole field of the earth. The anisotropy appears as a large-scale average effect resulting from small-scale differences in the resistivity of the materials in ascending and descending convection currents within the liquid core, which are deflected in the required form by the Coriolis acceleration. A numerical analysis of time-evolving magnetic fields in a model with anisotropic resistivity supports the basic mechanism of the dynamo effect. The differences in resistivity required to give regeneration for the core of the earth are too large to be accounted for by temperatuire differences but could conceivably result from differences in chemical composition.