APPEARANCE OF ACTIVE REGIONS AT THE END OF SOLAR CYCLE 24 AND AT THE BEGINNING OF CYCLE 25

The spatial-temporal picture of appear-ance of active regions and the relationship of their ap-pearance with the structure and development of a large-scale magnetic field were studied during the transition from solar cycle 24 to 25. During this period, solar ac-tivity is low, and therefore the dynamics of a large-scale magnetic field in the appearance of new active regions is most noticeable. We have used SDO/HMI data on the longitudinal magnetic field to determine the time and heliographic coordinates of the origin of an active re-gion, as well as daily WSO maps (Wilcox Solar Obser-vatory) to compare with the structure of the large-scale magnetic field. We have obtained the following results. During the transition from one cycle to another, new active regions appeared in half of the cases in the polari-ty inversion line of the large-scale magnetic field, and almost exclusively at the Hale boundaries in the corre-sponding hemispheres and solar cycles. In other cases, the places of appearance were unipolar regions of the large-scale magnetic field without a clear advantage in the location of the field regions according to the Hale law. The formation of active regions is preceded or ac-companied by changes in the structure of the large-scale magnetic field. At the same time, in the fine structure of the magnetic field in the photosphere we can observe an increase in the magnetic field network on a spatial scale of the size of supergranules and larger, as well as the appearance of small regions of a new magnetic field of both polarities. The appearing active regions were con-centrated in two narrow longitudinal zones that covered both hemispheres of the Sun. The new cycle began in the same longitudinal zones, where the activity of the old cycle decayed.