Solar magnetic fields and convection. IX

The solar magnetic fields observed in active regions and their residues are thought to be parts of toroidal field systems renewed every 11-yr cycle from a poloidal field. The latter may be either a reversing (dynamo) field or a non-reversing, primordial field. The latter view was held for some 70 yr, but the apparent reversals of the polar-cap fields in 1957-8 and the development of dynamo theory brought wide acceptance of the former. Here evidence for and against each model is considered. (Auth.)