Issue A&A Volume 449, Number 2, April II 2006 Page(s) 451 - 460 Section Astrophysical processes DOI 10.1051/0004-6361:20054241

A&A 449, 451-460 (2006)
DOI: 10.1051/0004-6361:20054241

A differential rotation driven dynamo in a stably stratified star

J. Braithwaite

Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Straße 1, Postfach 1317, 85741 Garching, Germany
    e-mail: jon@mpa-garching.mpg.de

(Received 22 September 2005 / Accepted 1 December 2005)

Abstract
We present numerical simulations of a self-sustaining magnetic field in a differentially rotating non-convective stellar interior. A weak initial field is wound up by the differential rotation; the resulting azimuthal field becomes unstable and produces a new meridional field component, which is then wound up anew, thus completing the "dynamo loop". This effect is observed both with and without a stable stratification. A self-sustained field is actually obtained more easily in the presence of a stable stratification. The results confirm the analytical expectations of the role of Tayler instability.

Key words: magnetohydrodynamics (MHD) -- stars: magnetic fields -- stars: rotation -- stars: evolution -- Sun: rotation -- instabilities

© ESO 2006

What is OpenURL?