Sectoral Structures of the Magnetic Field of the Sun and Their Differential Rotation in the 25th Activity Cycle

The results of 10 years of observations of the Sun’s magnetic fields using the STOP magnetograph at the Kislovodsk Mountain Astronomical Station are considered. The distribution of large-scale magnetic fields is analyzed. The change in the polarity of magnetic fields is investigated based on data from the STOP and SDO/HMI magnetographs. A comparison is also made between the lines of polarity inversion of large-scale magnetic fields and the position of solar filaments and prominences observed in the H line. During the solar activity cycle, sector structures repeatedly penetrate the polar regions, which is confirmed by both magnetographic observations and measurements in the H line. We observe signs that the inversion of the Sun’s global magnetic field occurred in the first half of 2025. Differential rotation of the large-scale field has been detected, manifested in characteristic 27- and 14-day variations at the equator, corresponding to two- and four-sector structures of the magnetic field. Four-sector magnetic structures demonstrate more pronounced differential rotation compared to two-sector structures, with a more noticeable slowdown from the equator to the poles. We also observe a north-south asymmetry in the differential rotation of magnetic fields.