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Differential rotation and magnetic fields in stellar interiors
Received 15 January 1999 / Accepted 30 May 1999
The processes contributing to the evolution of an initially weak magnetic field in a differentially rotating star are reviewed. These include rotational smoothing (akin to convective expulsion) and a list of about 5 instabilities, among them magnetorotational instability, buoyancy instability, and pinch-type instabilities. The important effects of thermal and magnetic diffusion on these instabilities are analyzed in some detail. The first instability to set in is a pinch-type instability. It becomes important in modifying the field configuration before magnetic buoyancy-driven instabilities set in. The evolution of an initially strong field remains a more open question, including the old problem whether dynamically stable magnetic equilibria exist in stars.
Key words: instabilities Magnetohydrodynamics (MHD) stars: magnetic fields stars: rotation Sun: rotation
© European Southern Observatory (ESO) 1999
Online publication: August 25, 1999