Generation of solar magnetic fields using a quadripolar seed fieldGeneration of solar magnetic fields using a quadripolar seed field
Faculty of Sciences. Physics
Department of Physics
PIERS 2006 Cambridge: Progress in Electromagnetics Research Symposium,
Progress in Electromagnetics Research Symposium (PIERS 2006), MAR 26-29, 2006, Cambridge, MA
(2006), p. 406-408
University of Antwerp
The exact solution for the kinematic dynamo problem in spherical coordinates r, theta, phi, o is given in Ref. 1. The velocity is supposed to be azimuthal and to be an arbitrary function of r and theta only. Using a bipolar seed field yielded a qualitative agreement with the sunspot butterfly diagram and the polar faculae butterfly diagram. Here we investigate the case that a quadripolar seed field resides in the Sun (maybe in the whole convective zone or rather only in the tachocline at the bottom of the convective zone). In fact some observations reveal a quadripolar contribution to some surface phenomena. A combination of a bipolar and a quadripolar field yields better agreement for a suitable choice of their amplitudes. The separation between the sunspot region and the polar faculae, although both are generated by the same mechanism, is manifest: the region where the radial variation of the angular frequency of the rotation vanishes.