Three-Dimensional Domino Model in Geodynamo

M. Yu. Reshetnyak

Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, ul. Bol’shaya Gruzinskaya 10, Moscow, 123995
Russia

Received August 18, 2012; in final form, November 29, 2013

Abstract—The Lagrangian formalism is applied to consider temporal evolution of the ensemble of interacting
magnetohydrodynamical cyclones governed by Langevin-type equations in a rotating medium. This problem is
relevant for fast-rotating convective objects such as the cores of planets and a number of stars, where the Rossby
numbers are far below unity and the geostrophic balance of the forces takes place. The paper presents the results
of modeling for both the two-dimensional (2D) case when the cyclones can rotate relative to the rotation axis
of the whole system in the vertical plane, and for the case of spatial rotation by two angles. It is shown that
variations in the heat flux on the outer boundary of the spherical shell modulate the frequency of the reversals
of the mean dipole magnetic field, which agrees with the three-dimensional (3D) modeling of the planetary
dynamo. Applications of the model for giant planets are discussed, and an explanation for some episodes in the
history of the geomagnetic field in the past is suggested.

Keywords: domino model, geomagnetic field, reversals, excursions, liquid core of the Earth

DOI: 10.1134/S1069351313030130

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