Magnetic polarity reversals

Image sequence showing the polarity reversal of the surface magnetic field in the course of a magnetic cycle developing in a magnetohydrodynamical numerical simulation of solar convection. The color scale codes the radial magnetic field, red-yellow for positive magnetic polarity and blue-green for negative, peaking here at +/- 0.04 Tesla. Even though the surface magnetic field is spatiotemporally very intermittent, a well-defined axisymmetric component is present, amounting to a magnetic dipole well aligned with the rotation axis. In this specific simulation the full magnetic cycle lasts about 78 years, corresponding to a pseudo-activity cycle of duration 39 years.

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Ghizaru, M., Charbonneau, P., et Smolarkiewicz, P.K., Magnetic cycles in a large eddy simulation of solar convection, The Astrophysical Journal Letters, 715, L133-L137; on ADS
Racine, E., Charbonneau, P., Ghizaru, M., Bouchat, A., et Smolarkiewicz, P.K., On the mode of dynamo action in a global large-eddy simulation of solar convection, The Astrophysical Journal, 735, id46; on ADS