Penetration of Dynamo‐generated Magnetic Fields into the Sun’s Radiative Interior

Abstract

Any large-scale magnetic fields present in solar/stellar radiative interiors have so far been thought to be primordial or residuals from extinct dynamos. We show that a regular cyclic dynamo can also be the origin of strong magnetic fields in the solar radiative tachocline and interior below. By exploiting a kinematic, mean-field flux-transport dynamo, we show that for a wide range of core-diffusivity values, from 109 cm2 s-1 down to a molecular diffusivity of 103 cm2 s-1, oscillatory dynamo fields penetrate below the tachocline. Amplitudes of these fields are in the range of ~1 kG to 3×103 kG, depending on core diffusivity value, when the dynamo produces ~100 kG peak toroidal fields in the overshoot tachocline. For a low enough core diffusivity (