1 Ecole Normale Supérieure, LPS,
UMR CNRS 8550,
24 Rue Lhomond, 75231 Paris Cedex 05, France
2 Ecole Normale Supérieure, LRA,
24 Rue Lhomond, 75231 Paris Cedex 05, France
3 Institut de Physique du Globe de Paris, UMR CNRS 7154,
4 place Jussieu, 75252 Paris Cedex 05, France
Received 2 October 2008; published 7 April 2009
Abstract.
We show that a model, recently used to describe all the dynamical regimes
of the magnetic field generated by the dynamo effect in the von Karman
sodium experiment, also provides a simple explanation of the reversals of
Earth's magnetic field, despite strong differences between both
systems. The validity of the model relies on the smallness of the magnetic
Prandtl number.