Irkutsk State University
Irkutsk, Russian Federation
Irkutsk, Russian Federation
Irkutsk, Russian Federation
We analyze features of current solar activity cycle 25 for the first three years of its development (2020–2022). Compared to cycle 24, the current cycle is shown to exceed the previous one in the number of sunspot groups (1.5 times), the number of flares (1.8 times), and the total flare index (1.5 times). We have found that distributions of sunspot groups during cycles 24 and 25 differ in maximum area. Solar cycle 25, unlike cycle 24, exhibits the most significant increase in the number of sunspot groups with areas up to 30 pmh and in the interval from 570 to 1000 pmh. In contrast to cycle 24, the degree of north-south asymmetry in cycle 25 is significantly reduced. This allows us to predict an increased height of cycle 25, as compared to cycle 24 (by 20–50 %), in accordance with the Gnevyshev—Ol rule, as well as the possible unimodal nature of the cycle.
solar activity cycle, sunspots, solar flares, north-south asymmetry
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18. Ishkov V.N. Sun in December 2009 - January 2010. Zemlya i Vselennaya [Earth and Universe]. 2010, no. 3, pp. 22-24. (In Russian).
19. Ishkov V.N. Space weather forecast: principles of the construction and boundaries of the implementation (experience of three cycles). Cosmic Res. 2017, vol. 55, no. 6, pp. 381-388. DOI:https://doi.org/10.1134/S0010952517060053.
20. Ishkov V.N. The Current 24th Cycle of Solar Activity in the Minimum Phase: Preliminary Results and Features of Development. Cosmic Res. 2020, vol. 58, pp. 436-443. DOI:https://doi.org/10.1134/S0010952520060064.
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22. Obridko V.N. Magnetic fields and activity indices. Plazmennaya geliofizika [Plasma Heliophysics]. 2008, vol. 1, p. 52. (In Russian).
23. Obridko V.N., Nagovitsyn Yu.A. Solnechnaya aktivnost’, tsiklichnost’ i metody prognoza [Solar activity, Cyclicity and Forecast Techniques]. Saint Petersburg, VVM Publ., 2017, 466 p. (In Russian).
24. Obridko V.N., Shelting B.D. Some anomalies in the evolution of global and large-scale magnetic fields on the Sun as predictors of some forthcoming low cycles. Pisma v Astronomicheskii zhurnal [Astron. Lett.] 2009, vol. 35, no. 4, pp. 279-285. (In Russian).
25. Olemskoy S.V., Kitchatinov L.L. Grand minima and north-south asymmetry of solar activity. Astrophys. J. 2013, vol. 777, iss. 1, article id. 71, p. 71. DOI:https://doi.org/10.1088/0004-637X/777/1/71.
26. Pishkalo M.I. Preliminary forecast of the 24th and 25th cycles of solar activity based on the correlation between the characteristics of the cycles. Kinematika i fizika nebesnikh til [Kinematics and Physics of Celestial Bodies]. 2008, vol. 24, no. 5, pp. 370-378. (In Ukrainian).
27. Vitinsky Yu.I., Kopecky M., Kuklin G.V. Statistika pyatnoobrazovatelnoi deyatelnosti Solntsa [Statistics of sunspot-forming activity of the Sun]. Moscow, Nauka Publ., 1986, 296 p. (In Russian).
28. URL: https://www.sidc.be/silso/forecasts (accessed February 15, 2023).
29. URL: https://www.sidc.be/silso/monthlyhemisphericplot (accessed February 15, 2023).
30. URL: https://www.swpc.noaa.gov/products/solar-cycle-progression (accessed February 15, 2023
