Statistical studies of low-power solar flares. Distribution of flares by area, brightness, and classes
Abstract and keywords
Abstract (English):
An electronic database has been created for 123801 solar flares that occurred on the Sun over the period from 1972 to 2010. It is based on catalogs of the Solar Geophysical Data (SGD) and Quarterly Bulletin on Solar Activity. A software package has been used for statistical data preprocessing. The first results revealed a number of new features in the distribution of parameters of solar flares, which differ from those obtained previously. We have found that more than 90% of all solar flares are low-power. The most numerous class comprises SF flares (64%). Flare activity shows a pronounced cyclicity and high correlation with Wolf numbers. The highest correlation coefficients indicate S and 1 solar flares. There is also a high correlation between individual flare classes: S and 1, 1 and (2–4). The results obtained previously [Mitra et al., 1972] which provide evidence of the prevalence of SN solar flares (47%) and the existence of significant peaks for SN and 1N flares, have not been confirmed. The distribution of the number of solar flares with increasing optical importance smoothly decreases without significant deviations. With increasing optical importance, solar flares are gradually redistributed toward an increase in brightness class. The excess of the number of SN and 1N solar flares present in the distributions obtained in [Mitra et al., 1972] are most likely associated with poor statistics.

solar activity, flares
Publication text (PDF): Read Download

1. Abramenko S.I., Dubov E.E., Ogir’ M.B., Steshenko N.E., Shaposhnikov E.F., Tsap T.T. Photometry of solar flares. Izvestiya KrAO [Bulletin of the Crimean Astrophysical Observatory]. 1960, vol. 23, pp. 341–361. (In Rus-sian).

2. Altyntsev A.T., Banin V.G., Kuklin G.V., Tomozov V.M. Solnechnye vspyshki [Solar Flares]. Moscow, Nauka Publ., 1982, 246 p. (In Russian).

3. Kopetskaya F., Kopetsky M. Characteristics of power chromospheric flares from Catalogues by Frittseva, Ko-petsky, Šhvestka. Issledovaniya po geomagnetizmu, aeronomii i fizike Solntsa [Research on Geomagnetism, Aer-onomy and Solar Phys.]. 1971, iss. 2, pp. 117–130. (In Russian).

4. Mitra R.K., Sarkar S.R., Das Gupta M.K. Some studies on solar optical flares reported under new classification. Indian J. Radio and Space Phys. 1972, vol. 1, p. 170.

5. Rossada V.M. Statistical analysis of 6600 flares for 1965–1966. Vestnik Kievskogo universiteta. Ser. Astronomiya [Bulletin of Kiev University]. 1977, no. 19, pp. 49–55. (In Russian).

6. Smith H., Smith E. Solnechnye vspyshki [Solar Flares]. Moscow, Mir Publ., 1966, 426 p. (In Russian).

7. Antalova A. Catalogue of the LDE flares (January 1969 – March 1986). Contr. Astron. Obs. Skalnatom Pleso. 1987, vol. 16, pp. 79–90.

8. Sotnikova R.T. Energy spectrum of X-ray flares associated with sunspot groups of different classes in three solar cycles. Geomagnetism and Aeronomy. 2010, vol. 50, no. 7, pp. 905–907.

9. Temmer M., Veronig A., Hanslmeier A., Otruba W., Messerotti M. Statistical analysis of solar Hα flares. Astron. Astrophys. 2001, vol. 375, pp. 1049–1061.

10. Warwik C.S. Solar flare frequency and observing-time patterns. Astrophys. J. 1965, vol. 142, no. 2, pp. 767–771.

11. Ward F., Cornevall R.F., Hendle R. Solar flare observations from a pair of matched instruments. Solar Phys. 1973, vol. 31, p. 131.

Login or Create
* Forgot password?