Impact of magnetohydrodynamic turbulence on thermal wind balance in the Sun

Abstract

Abstract The possible role of magnetorotational instability (MRI) and its driven magnetohydrodynamic (MHD) turbulence in the solar interior is studied on the basis of linear and non-linear theories coupled with physical parameters, assuming a solar rotation profile inverted from helioseismic observations and a standard model for the internal structure of the Sun. We find that the location of MRI is confined to the higher latitude tachocline and lower latitude near-surface shear layer. It is especially interesting that the MRI-active region around the tachocline closely overlaps with the area indicating a steep entropy rise, which is required from the thermal wind balance in the Sun. This suggests that the MRI-driven turbulence plays a crucial role in maintaining the thermal wind balance in the Sun via the exceptional turbulent heating and equatorward angular momentum transport. The warm pole existing around the tachocline might be a natural outcome of the turbulent activities energized by the MRI.