Volume 532, August 2011
|Number of page(s)||15|
|Published online||19 July 2011|
Magnetic confinement of the solar tachocline: II. Coupling to a convection zone
Laboratoire AIM Paris-Saclay, CEA/Irfu Université Paris-Diderot
2 LUTH, Observatoire de Paris, CNRS-Université Paris Diderot, Place Jules Janssen, 92195 Meudon, France
Accepted: 12 June 2011
Context. The reason for the observed thinness of the solar tachocline is still not well understood. One of the explanations that have been proposed is that a primordial magnetic field renders the rotation uniform in the radiation zone.
Aims. We test here the validity of this magnetic scenario through 3D numerical MHD simulations that encompass both the radiation zone and the convection zone.
Methods. The numerical simulations are performed with the anelastic spherical harmonics (ASH) code. The computational domain extends from 0.07R⊙ to 0.97R⊙.
Results. In the parameter regime we explored, a dipolar fossil field aligned with the rotation axis cannot remain confined in the radiation zone. When the field lines are allowed to interact with turbulent unstationary convective motions at the base of the convection zone, 3D effects prevent the field confinement.
Conclusions. In agreement with previous work, we find that a dipolar fossil field, even when it is initially buried deep inside the radiation zone, will spread into the convective zone. According to Ferraro’s law of iso-rotation, it then imprints on the radiation zone the latitudinal differential rotation of the convection zone, which is not observed.
Key words: Sun: interior / Sun: rotation / magnetohydrodynamics (MHD) / convection / magnetic fields
© ESO, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.