Solar magnetism: Observation and theory

Abstract

AbstractThis introductory review consists of four parts. The first is a discussion of the concentration of magnetic flux into small elements, the large electrical conductivity and the superadiabatic stratification as the main reasons for these “flux tubes”, their relationship to the mean field, and the observational evidence of the latter. The second briefly repeats the approximations and merits of kinematic mean field dynamos. In the form of the αω‐dynamo, this theory esplains the reversals, latitude migration, dipolar parity and other properties of the mean solar field. The third part treats the question of flux loss from the bottom of the convection zone, or in a transition layer beneath it. The last part discusses further dynamic aspects of the Sun's magnetism, e.g. models of limit cycles and models with chaotic behaviour and in particular the question of phase stability of the solar cycle.