Events

We carry out an unprecedentedly high-resolution simulation for the solar convection zone and succeed in reproducing the fast equator, poleward meridional flow, and near-surface shear layer (NSSL) simultaneously. The NSSL is one of the mysteries of solar physics. We thought the banana-cell-like convective structure was required for the fast equator, but it destroyed the NSSL. Thus we cannot reproduce the fast equator and NSSL simultaneously. Hotta & Kusano, 2021, Nature Astronomy recently found that we no longer need the banana cell for the fast equator since the magnetic field can transport the angular momentum. In that simulation, the fast equator is reproduced without artificial manipulation, but the NSSL is not obtained since the near-surface layer is not included. Here we carry out a new simulation that includes the layer and succeeds in producing the fast equator and the NSSL simultaneously. We find that the poleward flow is still the key for the NSSL. The high-Rossby number flow around the surface generates the poleward meridional flow. Then the magnetic tension on the poleward meridional flow maintains the NSSL.

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