Strong Field Dynamos in Rapidly Rotating Convection with no Inertia - David Hughes (University of Leeds)

David Hughes (University of Leeds)

Résumé

It is generally believed that the magnetic field generated by dynamo action in rapidly rotating bodies, such as the Earth, is strong ? in the sense that there are significant differences between the hydrodynamic convective state and the convection once dynamo action sets in. That said, obtaining strong field solutions numerically has proved to be extremely difficult. Most computational dynamo solutions only generate a weak field, with the convection being influenced only slightly by the generated magnetic field. One of the problems seems to be that the solutions are still dominated by inertia, whereas in the Earth, for example, inertia is believed to be negligible. Thus, to try to access the strong field solutions we here neglect the inertial terms from the outset, which of course has both physical and mathematical consequences. However, as we shall see, it does allow an exploration of both weak and strong field solutions and their underlying physics.