Magnetohydrodynamic model of the solar tachocline

The tachocline is a thin layer providing the transition from differential to uniform rotation in the upper region of the solar radiative zone, which can be explained as an effect of the magnetic field if the magnetic field lines are closed inside the radiative zone. It is shown that the confined field structure that is necessary for the tachocline formation can arise due to the penetration of meridional flow from the convective envelope to the radiative zone. The time for the distortion of the magnetic field by the penetrating flow is short compared to the time for diffusion to the penetration depth. The most long-lived mode of the poloidal field has a confined geometry, and the Ohmic lifetime of this mode exceeds the age of the Sun. The calculated distribution of the angular velocity in the radiative zone taking into account such a field shows a thin tachocline.