Abstract
Time series of daily numbers of solar Hα flares from 1955 to 1997 are studied by means of wavelet power spectra with regard to predominant periods in the range of ∼ 24 days (synodic). A 24-day period was first reported by Bai (1987) for the occurrence rate of hard X-ray flares during 1980–1985. Considering the northern and southern hemisphere separately, we find that the 24-day period is not an isolated phenomenon but occurs in each of the four solar cycles investigated (No. 19–22). The 24-day period can be established also in the occurrence rate of subflares but occurs more prominently in major flares (importance classes ≥ 1). A comparative analysis of magnetically classified active regions subdivided into magnetically complex (i.e., including a γ and/or δ configuration) and non-complex (α, β) reveals a significant relation between the appearance of the 24-day period in Hα flares and magnetically complex sunspot groups, whereas it cannot be established for non-complex groups. It is suggested that the 24-day period in solar flare occurrence is related to a periodic emergence of new magnetic flux rather than to the surface rotation of sunspots.
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References
Ambrož, P.: 1973, Bull. Astron. Inst. Czech. 24, 80.
Aschwanden, M.: 2002, Space Sci. Rev. 101, 1.
Bai, T.: 1987, Astrophys. J. 314, 795.
Balthasar, H. and Schüssler, M.: 1983, Solar Phys. 87, 23.
Balthasar, H., Schüssler, M., and Wöhl, H.: 1982, Solar Phys. 76, 21.
Balthasar, H., Vázquez, M., and Wöhl, H.: 1986, Astron. Astrophys. 155, 87.
Beck, J.: 1999, Solar Phys. 191, 47.
Bogart, R. S.: 1982, Solar Phys. 76, 155.
Brajša, R., Wöhl, H., Vršnak, B., Ruždjak, D., Sudar, D., Roša, D., and Hržina, D.: 2002, Solar Phys. 206, 229.
Bumba, V. and Howard, R.: 1969, Solar Phys. 7, 28.
Daubechies I.: 1990, IEEE Trans. Inform. Theory 36, 961.
Gaizauskas, V., Harvey, K. L., Harvey, J. W., and Zwaan, C.: 1983, Astrophys. J. 265, 1056.
Godoli, G., Mazzucconi, F., and Piergianni, I.: 1998, Solar Phys. 181, 295.
Grossman, A. and Morlet, J.: 1984, SIAM J. Math. Anal. 15, 723.
Henney, C. J. and Harvey, J. W.: 2002, Solar Phys. 207, 199.
Howard, R.: 1984, Ann. Rev. Astron. Astrophus. 22, 131.
Jetsu, L., Pohjolainen, S., Pelt, J., and Tuominen, I.: 1997, Astron. Astrophys. 318, 293.
Klimeš, J. and Křivsky, L.: 1981, Bull. Astron. Inst. Czech. 32, 222.
Klimeš, J. and Křivsky, L.: 1983, Graphic Catalogue of Spot Groups, Carrington Longitude-Time-Latitude for Cycle No. 20, Publ. Observatory Upice.
Oliver, R. and Ballester, J. L.: 1995, Solar Phys. 156, 145.
Pap, J., Tobiska, W. K., and Bouwer, A. D.: 1990, Solar Phys. 129, 165.
Pulkkinen, P. and Tuominen, I.: 1998, Astron. Astrophys. 332, 748.
Rodriguez Taboada, R. E. and Gil Moreno, G.: 1993, Solar Phys. 144, 399.
Sammis, I., Tang, F., and Zirin, H.: 2000, Astrophys. J. 540, 583.
Suzuki, M.: 1998, Solar Phys. 178, 259.
Temmer, M., Veronig, A., and Hanslmeier, A.: 2002, Astron. Astrophys. 390, 707.
Temmer, M., Veronig, A., Hanslmeier, A., Otruba, W., and Messerotti, M.: 2001, Astron. Astrophys. 375, 1049.
Temmer, M., Veronig, A., Rybák, J., and Hanslmeier, A.: 2003, Hvar Obs. Bull. 27, 59.
Torrence, C. and Compo, G. P.: 1998, Bull. Am. Meteor. Soc. 79, 61.
Veronig, A., Temmer, M., Hanslmeier, A., Otruba, W., and Messerotti, M.: 2002, Astron. Astrophys. 382, 1070.
Zięba, S., Maslowski, J., Michalec, A., and Kulak, A.: 2001, Astron. Astrophys. 377, 297.
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Temmer, M., Veronig, A., Rybák, J. et al. On the 24-day period observed in solar flare occurrence. Solar Physics 221, 325–335 (2004). https://doi.org/10.1023/B:SOLA.0000035044.49564.8e
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DOI: https://doi.org/10.1023/B:SOLA.0000035044.49564.8e