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Journal Articles EPL - Europhysics Letters Year : 2010

Morphology of field reversals in turbulent dynamos

Abstract

We show that the modes involved in the dynamics of reversals of the magnetic field generated by the flow of an electrically conducting fluid in a spherical domain, strongly depend on the magnetic Prandtl number Pm, i.e., the ratio between viscous and magnetic diffusivities. For Pm~1, the axial dipolar field reverses in the presence of a strong equatorial dipolar component, whereas for Pm<0.5, field reversals mostly involve axisymmetric modes, axial magnetic dipole and quadrupole coupled through a broken symmetry of the flow. Using symmetry arguments, we write a dynamical system for these three modes that qualitatively reproduces the main features of the reversals observed in direct simulations for small Pm.

Dates and versions

insu-03605331 , version 1 (11-03-2022)

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C. Gissinger, E. Dormy, S. Fauve. Morphology of field reversals in turbulent dynamos. EPL - Europhysics Letters, 2010, 90, pp.49001. ⟨10.1209/0295-5075/90/49001⟩. ⟨insu-03605331⟩
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