Open AccessPropagation of a dynamo field in the radiative interior of the Sun
Author(s) -
Garaud P.
Publication year - 1999
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1999.02338.x
Subject(s) - physics , dynamo , radiative transfer , solar dynamo , astrophysics , field (mathematics) , magnetohydrodynamics , dynamo theory , astronomy , magnetic field , optics , quantum mechanics , mathematics , pure mathematics
Large‐scale magnetic fields are believed to play an important role in the radiative zone of the Sun, in particular in the dynamical processes in the transition region between the convective and radiative zones (the tachocline). Also, they are probably responsible for the observed uniform rotation of the radiative zone. In that respect, since it has been suggested that the solar dynamo may lie near the outer edge of the tachocline, it is important to assess the question of how deep the dynamo field can penetrate, and whether it can influence significantly the dynamics of the solar interior. The magnetic cycle of the Sun is not strictly periodic, but undergoes random fluctuations in amplitude and phase. It is shown how the random fluctuations in the poloidal field diffuse into the radiative zone. An explicit solution for this diffusion process is given under certain simplifying assumptions. The result is then used together with some assumptions about the solar dynamo field to suggest that a field of order of 10 ‐1 G should be expected near the outer edge of the radiative zone, dropping rapidly to 10 ‐6 G beneath r=0.3 R ⊙ . This confirms the expectation that the dynamo field has a negligible effect on the dynamical processes taking place both in the tachocline and deeper in the radiative zone.