Global Evolution of Photospheric Magnetic Fields

Abstract

The main feature concerning the evolution of the large photospheric magnetic fields derived from synoptic maps as well as from H –alpha synoptic charts are reviewed. The significance of a verity of observations that indicate the presence of a high latitude component as a counterpart to the sunspot phenomenon at lower latitudes is reviewed. It is argued that these two components describe the global magnetic field on the sun. It is demonstrated that this scenario is able to link many phenomena observed on the sun (coronal emission, ephemeral active regions, geomagnetic activity, torsional oscillations, polar faculae and global modes in the magnetic field pattern) with the global magnetic activity.