Evolution of solar active regions: Detecting the emergence of new magnetic field through multifractal segmentation

Abstract

New emerging magnetic flux is identifed using a multifractal segmentation method used to investigate regularities in the evolution of active regions and activity complexes. The SOLIS, MDI SOHO, and SOT Hinode magnetograms were used. Observations of the active region NOAA 10488 on October 26-28, 2003 indicate considerable variability of areas of newmagnetic flux on a characteristic time scale of 1-2 h. Broadening of the multifractal spectrum in magnetogram sections corresponding to areas of new flux leads to their detection on segmented multifractal images corresponding to the minimal fractal dimensions. New regularities in the emergence of magnetic flux in the 24th solar cycle are studied using data obtained in 2010-2014. A positive correlation of the time variations of areas of new magnetic flux of N and S polarities is predominant at all stages in the development of the cycle. A gradual decrease in the correlation coefficient during 2010-2014 is associated with the progressive complexity of the relationships among active regions, which leads to their clustering into activity complexes.