SOLAR ACTIVITY AND RECURRENCES IN MAGNETIC-FIELD DISTRIBUTION

A study of the Mount Wilson magnetic-field synoptic chart material divided into latitude zones for the interval 1959-67, and a comparison of the data with sunspot groups have provided a better understanding of the structure of the background-field pattern and its relation to activity. The interaction of old and new fields within the pattern seems to result in long-lived sections of alternating polarity in both hemispheres. We postulate subsurface sources with rotation periods of about 27 days which produce active regions over a longitude zone of some tens of degrees. There is a tendency for the background-field features with strong fields to resist to some extent the shearing effects of differential rotation. A prediction is made concerning the nature of the interplanetary magnetic field above the ecliptic. © 1969 D. Reidel Publishing Company.