Abstract
The theory of Yang, Chang, and Harvey (1983) is used to perform this analysis of the big active region AR 4711 of February, 1986, which produced many big and strong flares with proton events, SIDs and other significant geophysical effects. The various physical quantities are calculated, yielding for ΔM a value up to 5.36 × 1032 erg, sufficient to supply the energies of the observed flare activities in this active region. Observations of the twisting of the entire quadrupolar sunspot group and the variations of the magnetic energies with dates all agree with our theoretical expectations.
It is found that the maximum of the f number of flare activity occurred about one day later than the maximum of ΔM, i.e., the release of free magnetic energy to produce flare activity requires a time interval of about one day. This, together with the formula of ΔM can be useful in solar prediction work.
Similar to the famous active region of August 1972 (McMath 11976), the separation of both footpoints of the new emerging magnetic flux along the neutral line of the old bipolar group led to the formation of a compact quadrupolar sunspot group, with strong twisting of penumbral filaments.
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References
Allen, C. W.: 1976, Astrophysical Quantities, The Athlone Press, New York, A7;88.
Bray, R. J. and Loughhead, R. E.: 1965, Sunspots, John Wiley and Sons Inc., New York, p. 216.
Chen, Z.-C. and Wang, J.-X.: 1986, Solar Phys. 103, 317.
Galloway, D. J. and Weiss, N. O.: 1981, Astrophys. J. 243, 945.
Hagyard, M. J., Hong Qinfang, Ding Youji, and Smith, J. B. Jr.: 1988, Acta Astrophys. Sinica 8, 124.
Jette, A. D.: 1970, J. Math. Ann. Appl. 29, 109.
Křivský, L.: 1974, Bull. Astron. Inst. Czech. 25, 62.
Lüst, R. and Schlüter, A.: 1954, Z. Astrophys. 34, 263.
Nakagawa, Y.: 1976, Space Sci. Rev. 19, 459.
Nakagawa, Y. and Raadu, M. A.: 1972, Solar Phys. 25, 127.
Nakagawa, Y., Raadu, M. A., Billings, D. E., and McNamara, D.: 1971, Solar Phys. 19, 72.
Nishi, K. and Makita, M.: 1973, Publ. Astron. Soc. Japan 25, 51.
Schatzman, E.: 1961, Ann. Astrophys. 24, 251.
Schatzman, E.: 1965, in R. Lüst (ed.) Stellar and Solar Magnetic Fields, North-Holland Publ. Co., Amsterdam, p. 337.
Simon, G. W. and Weiss, N. O.: 1970, Solar Phys. 13, 85.
Tanaka, K. and Nakagawa, Y.: 1973, Solar Phys. 33, 187.
Wang, Z.-Z. and Lin, Y.-Z.: 1985, in C. de Jager and Chen Biao (eds.), Proceedings of Kunming Workshop on Solar Physics and Interplanetary Traveling Phenomena, Science Press, Beijing, China, p. 233.
Wu, S. T. and Hu, Y. Q.: 1982, in V. N. Obridko and E. V. Ivanov (eds.), Sun-Earth Council, Proceedings of Crimean Solar Maximum Year (SMY) Workshop, Academy of Sciences, IZMIRAN, U.S.S.R., Vol. 1, p. 148.
Yang, H.-S. and Chang, H.-M.: 1980, Acta Astron. Sinica 21, 136.
Yang, H.-S. and Chang, H.-M.: 1981, Chinese Astron. Astrophys. 5, 77.
Yang, H.-S., Chang, H.-M., and Li, W.-B.: 1980, Acta Astron. Sinica 21, 143.
Yang, H.-S., Chang, H.-M., and Li, W.-B.: 1981, Chinese Astron. Astrophys. 5, 84.
Yang, H.-S., Chang, H.-M., and Harvey, J. W.: 1983, Solar Phys. 84, 139.
Yang, H.-S., Chang, H.-M., and Li, W.-B.: 1985, in C. de Jager and Chen Biao (eds.), Proceedings of Kunming Workshop on Solar Physics and Interplanetary Traveling Phenomena, Science Press, Beijing, China, p. 219.
Yin, Q.-F. and Luo, S.-G.: 1978, Studia Astron. Sinica 1, 61.
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Visiting Professor from the Astrophysics Division, Geophysics Department, Peking University, Beijing, China.
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Yang, HS., Hong, Q.F. & Ding, Y.J. A constant-α force-free-field analysis of the active region AR 4711 of February, 1986. Sol Phys 117, 57–67 (1988). https://doi.org/10.1007/BF00148572
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DOI: https://doi.org/10.1007/BF00148572