Mechanisms for magnetic field reversals.
We present a review of the different models that have been proposed to explain reversals of the magnetic field generated by a turbulent flow of an electrically conducting fluid (fluid dynamos). We then describe a simple mechanism that explains several features observed in palaeomagnetic records of the Earth's magnetic field, in numerical simulations and in a recent dynamo experiment. A similar model can also be used to understand reversals of large-scale flows that often develop on a turbulent background.
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Laboratoire de Physique Statistique, CNRS UMR 8550, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France. petrelis@lps.ens.fr
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