A model for the sharp transition from differential rotation in the sol
ar convection zone to rigid rotation in the radiative interior is pres
ented. Differential rotation in the radiative zone is shown to be quen
ched efficiently by an internal magnetic field. The poloidal field amp
litude, B-0 is the input parameter for our model which determines the
transition layer thickness and the toroidal field strength. It is illu
strated analytically and confirmed numerically that a rather small fie
ld, B-0 = 10(-4) Gauss, suffices to satisfy the helioseismological res
trictions on the depth of the differential rotation penetration below
the convection zone. The transition layer thickness decreases further
with increasing B-0. The toroidal field amplitude B similar or equal t
o 200 Gauss is almost independent of B-0.