Introduction to galactic dynamos
arXiv:astro-ph/0411739
Abstract
A review of galactic magnetic fields is given with emphasis on simple analytical solutions of relevant equations and detailed comparison with observations. It is shown that mean-field dynamo theory, in its simplest form, is in a remarkably good agreement with observations of galactic magnetic fields. It is argued that the disc-halo connection can play crucial role in the nonlinear evolution of regular magnetic fields in spiral galaxies by driving flux of magnetic helicity from the disc, thus supporting healthy dynamo action.
58 pages, 8 figures; to be published in "Mathematical Aspects of Natural Dynamos", EDP Press