A Morphological Study of Unipolar Magnetic Fields and the Relationship with Sunspots

A morphological examination of the Kitt Peak photospheric magnetic maps has been made over three sunspot cycles in order to study the morphology of unipolar magnetic regions and sunspots. Unipolar magnetic regions (positive and negative) are a series of weak, large-scale longitudinal bands, extending from 0°to 60° in latitude and alternatively aligned in longitude. The first finding is that unipolar regions grow and decay with the sunspot cycle and thus are likely to be a part of the basic solar (dipolar) magnetism, not old active regions located below 30° in latitude (as have long been considered). The second finding is that positive pores and single spots (coalesced pores, often called ‘isolated’ spots or ‘independent’ spots) occur in a positive unipolar region (vice vera). Thus, the unipolar regions could be the source of single spots. The third finding is that a pair (positive and negative) of dense clusters of pores, single spots and large spots (a coalesced single spots) occur at each side of the boundary of neighboring (positive and negative) unipolar regions, forming pairs of spots across the boundary; in fact, pairs of spots do not occur in the middle of a unipolar region. The boundaries of unipolar regions are tentatively identified as the Hale boundary, where solar activities (including solar flares) occur). Thus, it is suggested that the presently accepted magnetic tube theory may need a new consideration.