The Nonlinear Solar Dynamo and Differential Rotation - a Taylor Number Puzzle
Abstract
We consider dynamically consistent mean-field dynamos in a spherical shell of incompressible fluid. The generation of magnetic field and differential rotation is parameterized by the α- and Λ-effects, respectively. Extending previous investigations, we include now the cases of moderate and rapid rotation in the sense that the inverse Rossby number can approach or exceed unity: This can lead to disk-shapedΩ-contours, which are in better accordance with recent results of helioseismology than cylindricalΩ-contours. On the other hand, in order to obtain αω-dynamo cycles the Taylor number has to be so large, that eventually cylindrical Ω-contours become unavoidable (cf. Taylor-Proudman theorem). We discuss the different possibilities in a state diagram, where the inverse Rossby number and the relative correlation length are taken as the elementary parameters for mean-field dynamos.
- Publication:
-
Solar Physics
- Pub Date:
- July 1990
- DOI:
- 10.1007/BF00154160
- Bibcode:
- 1990SoPh..128..243B
- Keywords:
-
- Dynamo Theory;
- Helioseismology;
- Solar Magnetic Field;
- Solar Rotation;
- Magnetic Field Configurations;
- Nonlinear Equations;
- Planetary Waves;
- Spherical Shells;
- Solar Physics;
- Magnetic Field;
- Previous Investigation;
- Recent Result;
- Correlation Length;
- Spherical Shell