Semi-regularities in the photospheric magnetic fields

Abstract

Using Stanford large-scale magnetic field synoptic charts of rotation 1676 to 1739 and by delineating LLUMR, i.e., long-lived unipolar magnetic regions of both polarities surviving at least for four solar rotations, the semi-regular nature of their photospheric magnetic field pattern and their rotational properties have been examined. The investigation demonstrates the existence of regularities in the background field patterns as shown from the regular patterns of LLUMR rows and streams. This confirms the results of Bumba and Howard concerning regularities in large-scale photospheric magnetic field patterns. LLUMR streams seem to be arranged in a wave pattern of alternating polarities. Coronal holes and associated sections of photospheric field patterns suffer differential rotation. The rotation rates of the background field patterns which are not associated with the coronal holes are different from those which are.