Magnetic configurations produced by hydromagnetic dynamos
Abstract:The dynamo mechanism is a generic physical mechanism which excites large-scale magnetic fields in stars (including the Sun), planets and galaxies. The dynamo action is based on two generators, i.e. differential rotation and the so-called α effect associated with mirror asymmetry of rotating convection or turbulence. We discuss why dynamo excitation gives dynamo waves of dipole symmetry in spherical shells and steady quadrupole configurations in galactic discs. The key factor determining the magnetic configuration is the direction, which gives the maximal shear of differential rotation. Dynamos with the shear directed along the shell grow steadily while dynamos based on the shear directed across the shell result in dynamo wave configurations.
Document Type: Research Article
Affiliations: Department of Physics, Moscow State University, Moscow, Russia
Publication date: 2007-02-01