From reversing to hemispherical dynamos.
We show that hemispherical dynamos can result from weak equatorial symmetry breaking of the flow in the interior of planets and stars. Using a model of spherical dynamo, we observe that the interaction between a dipolar and a quadrupolar mode can localize the magnetic field in only one hemisphere when the equatorial symmetry is broken. This process is shown to be related to the one that is responsible for reversals of the magnetic field. These seemingly very different behaviors are thus understood in a unified framework.
Gallet
Basile
B
Laboratoire de Physique Statistique de l'Ecole Normale Supérieure, UMR CNRS 8550, 24 Rue Lhomond, 75231 Paris Cedex 5, France.
Pétrélis
François
F
D003198:Computer Simulation; D004735:Energy Transfer; D008962:Models, Theoretical; D012212:Rheology / Q000379:methods*