Variations of some solar activity indices and magnetic fields of coronal holes of cycle 25
- Authors: Andreeva O.A.1, Illarionov E.A.2,3
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Affiliations:
- Crimean Astrophysical Observatory RAS (CrAO RAS)
- Lomonosov Moscow State University (MSU)
- Moscow Center of Fundamental and Applied Mathematics
- Issue: Vol 65, No 5 (2025)
- Pages: 590-598
- Section: Articles
- URL: https://journal-vniispk.ru/0016-7940/article/view/352718
- DOI: https://doi.org/10.7868/S3034502225050035
- ID: 352718
Cite item
Abstract
Variations in the sunspot areas and indices, as well as the areas and magnetic fluxes of coronal holes are considered for the first five years of Cycle 25. The analysis is based on the source data from https://observethesun.com. The magnetic fluxes of coronal holes were calculated from the synoptic maps of magnetic fields obtained from two independent instruments: the Helioseismic and Magnetic Imager/Solar Dynamics (HMI/SDO) and the Solar Operational Prediction Telescope/Kislovodsk Mountain Astronomical Station of the Pulkovo Observatory (STOP/KGAS). The study of variations of the monthly indices and sunspot areas in both hemispheres revealed a pronounced asymmetry in the sunspot production rate during the period under consideration in favor of the southern hemisphere. In the same period, a significant asymmetry was also observed in the occurrence time and amplitude of polar and low-latitude coronal holes. At the beginning of the period from January 2020 to April 2022, the main contribution to the total area was made by polar coronal holes. Then, the contribution of low-latitude coronal holes dominated until the end of the period under consideration, although at certain moments the contribution of both types of coronal holes was significant. A comparative analysis of the dynamics of magnetic fluxes of coronal holes based on the HMI/SDO and STOP/KGAS synoptic maps for the same period (2014-2024) showed a good agreement between the results. This is a strong argument in favor of a regular use of domestic instruments, in particular STOP/KGAS, in studying the evolution of solar magnetic fields.
About the authors
O. A. Andreeva
Crimean Astrophysical Observatory RAS (CrAO RAS)
Author for correspondence.
Email: olga@craocrimea.ru
Nauchny, Russia
E. A. Illarionov
Lomonosov Moscow State University (MSU); Moscow Center of Fundamental and Applied Mathematics
Email: egor.illarionov@math.msu.ru
Moscow, Russia; Moscow, Russia
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