The Dynamical Regime in the Earth's Core

Wednesday, March 20, 2002 - 2:30pm - 3:30pm
Keller 3-180
Christopher Jones (University of Exeter)
An outstanding problem with current geodynamo simulations is that the parameters appropriate to the Earth's core cannot be reached because of numerical difficulties. We can, however, analyse the results available to see whether an asymptotic regime has been reached. Much lower Ekman numbers can be achieved if planar geometry rather than spherical geometry is used. Recent results from a plane layer model with rotation and gravity inclined to each other will be discussed. This model sheds light on how Taylor states are achieved in strongly supercritical dynamo models. The power spectrum and the associated ohmic dissipation will also be considered. Various dynamical regimes are possible, and the magnitude of the heat flux passing through the core is shown to be a key parameter in determining the actual dynamical regime achieved.