Large-scale magnetic fields in magnetohydrodynamical solar convection

Snapshot in Mollweide projection of the toroidal magnetic field component at the interface between the convection zone and underlying stably stratified fluid layers. The toroidal component is that oriented in the longitudinal direction (horizontally on this Mollweide projection), and rendered here on a color scale where red to yellow denotes an increasingly strong positive component (pointing to the right, in the prograde direction with respect to rotation), and blue to green to increasingly strong negative component. Even though the magnetic field is spatiotemporally very intermittent, a clear axisymmetric component is present, antisymmetric about the equatorial plane and peaking here at +/- 0.3 Tesla. This toroidal magnetic flux system is believed to be the origin of the magnetic flux ropes giving rise to sunspots upon buoyant rise through the convection zone and emergence in the photosphere.

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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