STRUCTURE AND CYCLIC EVOLUTION OF LARGE-SCALE SOLAR MAGNETIC-FIELDS

The global magnetic field of the Sun is regarded as consisting of 4 ma in field systems: 1) the axial dipole field, which is most pronounced at polar latitudes (phi > similar to 50 degrees); 2) the inclined dipo le field in the equatorial region (phi < similar to 50 degrees); 3) th e quadrupole component (a system of super giant cells with a size of s imilar to 80 degrees -110 degrees) that manifest itself in the form of a 4-sector field structure; and 4) the multipole component of orders higher than quadrupole. The global field and each of its components ar e quantitatively characterized by the total and partial magnetic field indices. The absolute and relative contribution of each field compone nt in different phases of the solar cycle are displayed for solar cycl es 20, 21 and 22. The physical meaning of solar cycle reference points is discussed.