Constraints on angular momentum transport in the Sun from simula- tions of the tachocline

The tachocline is a thin shear layer located near the interface between the uniformly rotating radiative zone and the differentially rotating convective zone in the Sun. Indeed, helioseismic observations (Schou et al. 1998; Gough 2007) reveal that the base of the convection zone has an angular velocity profile Ωcz(θ) consistent with Ωcz(θ) = Ωeq(1− a cos 2 θ − b cos θ) with Ωeq = 2.9× 10 s, a = 0.17, b = 0.08 , (1) where θ is the co-latitude, whereas less than 30,000 km deeper (for r < 0.67r⊙) the radiative zone is rotating with a constant angular velocity Ωrz(θ) = 0.93Ωeq . (2)