Spatial arrangement and energy of strong flares in solar cycle 24

  • Z.S. Akhtemov Crimean Astrophysical Observatory


In solar cycle 24 (2009–2015, Carrington rotations CR 2091–CR 2168) we have examined 1512 optical flares accompanied by X-ray emission with a power of f ≥ 5*10-6 wm-2 in the range of 1–8 Å. When comparing the characteristics of flares it was found that in a given period of time the S-hemisphere of the Sun is more active by quantity and power of flares than the N-hemisphere. 578 strong flares were recorded in the N-hemisphere of the Sun and 934 flares – in the S-hemisphere. For the entire period of observations there are several longitudinal intervals with increased activity of flares. They exist for the entire time interval of 2091–2168 Carrington rotations. Active longitudes in one hemisphere at the same time, with a high probability, are longitudes with low flare activity in other hemisphere and vice versa. In one and the same range of longitudes flare activity is “continuously” observed within 5-9 rotations. Over 78 rotations in cycle 24 such a long continuous activity occurred twice in each hemisphere. We show the distribution of the number of flares in cycles 22, 23 and 24 over 37, 68 and 78 rotations, re-spectively, as well as the distribution of the number of flares in time over 5.8 years in cycle 24. There is a north-south asymmetry in the distribution of the number of flares and capacity of flares in longitude and quasi-periodicity in the north-south asymmetry of the distribution of the number of flares in time.


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How to Cite
Akhtemov Z., 2016. Izvestiya Krymskoi Astrofizicheskoi Observatorii, vol. 112, no. 2, pp. 6-14. Available at: (Accessed: 5December2020)
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