Events

In the solar interior, strong latitudinal differential rotation persists throughout most of the convective zone (CZ). At the base of the CZ, this differential rotation transitions across a narrow shear layer, known as the “tachocline”, to rigid rotation in the radiative zone (RZ) below. The origin of the tachocline is a longstanding mystery of fluid dynamics, given the tendency of shear to spread inward relatively quickly compared to the solar age. We explore three-dimensional magnetohydrodynamic simulations of a solar-like CZ-RZ system, in which the magnetic field from the convective dynamo spreads into the RZ and confines a tachocline. For the first time, our simulations are able to confine tachoclines in the computationally challenging regime of “radiative spread”, wherein the large-scale meridional circulation spreads the differential rotation inward, as is expected to occur in the Sun. These new simulations represent a major breakthrough from prior work, which, for computational tractability, has been focused on the non-solar regime wherein viscosity (believed to be negligible in the Sun) spreads the differential rotation inward. We conclude with a summary of this recent progress toward solving the tachocline problem and outline avenues for further research.

Watch the recording.