  The property of inhomogeneous turbulence in conducting fluids to expel
large-scale magnetic fields in the direction of decreasing turbulence intensity
is shown as important for the magnetic field dynamics near the base of a
stellar convection zone. The downward diamagnetic pumping confines a fossil
internal magnetic field in the radiative core so that the field geometry is
appropriate for formation of the solar tachocline. For the stars of solar age,
the diamagnetic confinement is efficient only if the ratio of turbulent
magnetic diffusivity of the convection zone to the (microscopic or turbulent)
diffusivity of the radiative interiour is larger than 10^5. Confinement in
younger stars require still larger diffusivity ratio. The observation of
persistent magnetic structures on young solar-type stars can thus provide
evidences for the nonexistence of tachoclines in stellar interiors and on the
level of turbulence in radiative cores.
