Abstract
Complex sunspots in four active regions of April and May 1980, all exhibiting regions of magnetic classification delta, were studied using data from the NASA Marshall Space Flight Center vector magnetograph. The vector magnetic field structure in the vicinity of each delta was determined, and the location of the deltas in each active region was correlated with the locations and types of flare activity for the regions. Two types of delta-configuration were found to exist, active and inactive, as defined by the relationships between magnetic field structure and activity. The active delta exhibited high flare activity, strong horizontal gradients of the longitudinal (line-of-sight) magnetic field component, a strong transverse (perpendicular to line-of-sight) component, and a highly non-potential orientation of the photospheric magnetic field, all indications of a highly sheared magnetic field. The inactive delta, on the other hand, exhibited little or no flare production, weaker horizontal gradients of the longitudinal component, weaker transverse components, and a nearly potential, non-sheared orientation of the magnetic field. We conclude that the presence of such sheared fields is the primary signature by which the active delta may be distinguished, and that it is this shear which produces the flare activity of the active delta.
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References
Bray, R. J. and Loughhead, R. E.: 1964, Sunspots, Chapman and Hall, Ltd., London.
Cook, F. E. and Davies, P.: 1979, in R. F. Donnelly (ed.), Solar-Terrestrial Prediction Proceedings 1, 229.
Golovko, A. A., Kasinsky, V. V., and Klochek, N. N.: 1981, Crimean Solar Maximum Year Selected Reports, Moscow, p. 19.
Hagyard, M. J., West, E. A., Tandberg-Hanssen, E., Smith, J. E., Henze, W., Jr., Beckers, J. M., Bruner, E. C., Hyder, C. L., Gurman, J. B., Shine, R. A., and Woodgate, B. E.: 1981, in L. F. Cram and J. H. Thomas (eds.), The Physics of Sunspots, Sacramento Peak Observatory, Sunspot, New Mexico (USA), p. 213.
Hagyard, M. J., Cumings, N. P., West, E. A., and Smith, J. G.: 1982, Solar Phys. 80, 33.
Kjeldseth Moe, O. and Maltby, P.: 1969, Solar Phys. 8, 275.
Kunzel, H.: 1960, Astron. Nachr. 285, 271.
McKenna-Lawlor, S. M. P.: 1981, Chromospheric and Photospheric Evolution of an Extremely Active Solar Region in Solar Cycle 19, NASA Contractor Report 3377.
Patty, S. R.: 1981, in L. E. Cram and J. H. Thomas (eds.), The Physics of Sunspots, Sacramento Peak Observatory, Sunspot, New Mexico (USA), p. 64.
Sakurai, K.: 1967, Rep. Ionos. Space Res. Japan 21, 113.
Sakurai, K.: 1969, J. Geomag. Geoelec. 21, 463.
Sakurai, K.: 1970, Planetary Space Sci. 18, 33.
Severny, A. B.: 1965, in R. Lüst (ed.), Stellar and Solar Magnetic Fields, p. 238.
Su, Q.-R.: 1982, Solar Phys. 75, 229.
Von Klüber, H.: 1948, Z. Astrophys. 24, 121.
Warwick, C. S.: 1966, Astrophys. J. 145, 215.
Wu, S.-T., Hu, Y. Q., Krall, K. R., Hagyard, M. J., and Smith, J. B., Jr.: 1984, Solar Phys. 90, 117.
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NASA Graduate Student Research Fellow.
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Patty, S.R., Hagyard, M.J. Delta-configurations: Flare activity and magnetic-field structure. Sol Phys 103, 111–128 (1986). https://doi.org/10.1007/BF00154862
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DOI: https://doi.org/10.1007/BF00154862