Polar regions activity and the prediction of the height of the solar cycle 25 Solar Cycle 25

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Serge Koutchmy
Boris Filippov
E. Tavabi
J-C. Noëns
O. Wurmser

Abstract

The forthcoming solar cycle (SC) 25 was believed to be rather low when the sunspot number (SN) is used as a measure of the activity level. The most popular prediction was made by the NOAA/NASA Solar Cycle 25 Prediction Panel in 2019, including works based on dynamo-type models. However, we discovered that the height of SC25 could be high, using different observations for measurements of the level of the polar-region activity above the limb at high latitudes several years before the start of SC25 and also after its beginning in 2020. The polar-region activity, which we consider, seems to be related to the polar coronal-hole (CH) activity, and it was significantly higher before SC25 than before SC24. It is also possibly reflected in the so-called chromospheric prolateness observed at solar minimum. Accordingly, we suggest that SC25 could indeed be significantly higher than SC24, which was a very low SN cycle.

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Article Details

How to Cite
Koutchmy S., Filippov B., Tavabi E., et al., 2022. Acta Astrophysica Taurica, vol. 3, no. 2, pp. 12-16. Available at: https://astrophysicatauricum.org/index.php/aat/article/view/23 (Accessed: 6July2022)
Section
Magnetism and activity of the Sun and stars – 2021 Conference proceedings