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Geomagnetism and Aeronomy

, Volume 58, Issue 7, pp 916–924 | Cite as

Study of Variations of Some Characteristics of the Giant Coronal Hole of 2015–2017

  • O. A. Andreeva
  • Z. S. Akhmetov
  • V. M. Malashchuk
  • R. K. Zhigalkin
Article

Abstract

Analysis of images of the full solar disk obtained by ground-based (BST-2, CrAO RAS) and space-based (SDO/AIA, SDO/HMI) instruments and the potential approximation method revealed some features of the evolution of a long-lived coronal hole (CH) of 2015–2017. Variations in such CH characteristics as the area, intensity, magnetic field (MF) strength, and magnetic flux are studied. The study of the change in the area and average intensity of the CH contour at different heights has shown that changes in its area throughout the entire period occur almost synchronously within the boundaries determined by model calculations at the photospheric level and by observations of the Sun in the chromosphere and corona. The average CH intensity depends on the moment of its evolution: it varies from the intensity of the undisturbed region to the CH maximum intensity. This process lasts about the same time as the increase in the CH area. The intensity of the He I 10830 Å (He I) line occurs in antiphase with the decrease in the intensity in the Fe XII 193Å (Fe XII) line. This paper shows that this CH has significantly reduced the magnetic flux in a large part of the Sun in a time interval of almost a year and a half. Even when the CH began to collapse noticeably, the magnetic field strength and the magnetic flux continued to decrease.

Notes

ACKNOWLEDGMENTS

This study was supported in part by the Russian Foundation for Basic Research, project nos. 16-42-910467 r_a and 17-42-92017 r_a.

REFERENCES

  1. 1.
    Abramenko, V.I., Yurchyshyn, V.B., and Watanabe, H., Parameters of the magnetic flux inside coronal holes, Sol. Phys., 2009, vol. 260, pp. 43–57.CrossRefGoogle Scholar
  2. 2.
    Bumba, V., Klvana, M., and Sykora, J., Coronal holes and their relation to the background and local magnetic fields, Astron. Astrophys., 1995, vol. 298, pp. 923–933.Google Scholar
  3. 3.
    Fainshtein, V.G. and Rudenko, G.V., Multi-Wavelength Investigations of Solar Activity (IAU Symposium), Eds., Stepanov, A.V., Benevolenskaya, E., and Kosovichev, A.G., Cambridge University Press, 2004, vol. 223, p. 379.Google Scholar
  4. 4.
    Harvey, J.W. and Sheeley, N.R., Coronal holes and solar magnetic fields, Space Sci. Rev., 1979, vol. 23, pp. 139–158.Google Scholar
  5. 5.
    Harvey, K.L., Harvey, J.W., and Sheeley, N.R., Magnetic measurements of coronal holes during 1975–1980, Sol. Phys., 1982, vol. 79, pp. 149–160.CrossRefGoogle Scholar
  6. 6.
    Kahler, S.W., Davis, J.M., and Harvey, J.W., Comparison of coronal holes observed in soft X-ray and HE I 10830 A spectroheliograms, Sol. Phys., 1983, vol. 87, pp. 47–56.CrossRefGoogle Scholar
  7. 7.
    Kahler, S., Jibben, P., and Deluca, E.E., TRACE observations of changes in coronal hole boundaries, Sol. Phys., 2010, vol. 262, pp. 135–147. doi 10.1007/s11207-010-9517-4CrossRefGoogle Scholar
  8. 8.
    Levine, R.H., Open magnetic fields and the solar cycle. I. Photospheric sources of open magnetic flux, Sol. Phys., 1982, vol. 79, pp. 203–230.CrossRefGoogle Scholar
  9. 9.
    Nolte, J.T., Krieger, A.S., Timothy, A.F., et al., Coronal holes as sources of solar wind, Sol. Phys., 1976, vol. 46, pp. 303–322.CrossRefGoogle Scholar
  10. 10.
    Obridko, V.N. and Shelting, B.D., Coronal holes as indicators of large-scale magnetic fields in the corona, Sol. Phys., 1989, vol. 124, pp. 73–80.CrossRefGoogle Scholar
  11. 11.
    Obridko, V.N., Fomichev, V., Kharshiladze, A.F., et al., Analyses and modelling of coronal holes observed by Coronas-1. I. Morphology and magnetic field configuration, Astron. Astrophys. Trans., 2000, vol. 18, pp. 819–828.CrossRefGoogle Scholar
  12. 12.
    Obridko, V.N., Shelting, B.D., Livshits, I.M., and Askerov, A.B., Relationship between the contrast of coronal holes and parameters of the solar wind streams, Astron. Rep., 2009, vol. 53, no. 11, pp. 1050–1058.CrossRefGoogle Scholar
  13. 13.
    Robbins, S., Henney, C.J., and Harvey, J.W., Solar wind forecasting with coronal holes, Sol. Phys., 2006, vol. 233, pp. 265–276.CrossRefGoogle Scholar
  14. 14.
    Schrijver, C.J. and DeRosa, M.L., Photospheric and heliospheric magnetic fields, Sol. Phys., 2003, vol. 212, pp. 165–200.CrossRefGoogle Scholar
  15. 15.
    Stepanyan, N.N. and Malanushenko, E.V., Linking coronal holes with surrounding magnetic fields, Izv. Krym. Astrofiz. Obs., 2001, vol. 97, pp. 76–80.Google Scholar
  16. 16.
    Stepanyan, N.N., Akhtemov, Z.S., Fainshtein, V.G., et al., Height stratification and polar reversal of the Sun’s magnetic fields in cycles 21–23, Geomagn. Aeron. (Engl. Transl.), 2013, vol. 53, no. 8, pp. 957–961.Google Scholar
  17. 17.
    Veselovsky, I.S., Persiantsev, I.G., Rusanov, A.Yu., et al., One-parameter representation of the daily averaged solar-wind velocity, Sol. Syst. Res., 2006, vol. 40, no. 5, pp. 427–431.CrossRefGoogle Scholar
  18. 18.
    Wang, Y.-M., Semiempirical models of the slow and fast solar wind, Space Sci. Rev., 2012, vol. 172, pp. 123–143.CrossRefGoogle Scholar
  19. 19.
    Wang, Y.-M., Hawley, S.H., and Sheeley, N.R., The magnetic nature of coronal holes, Science, 1996, vol. 271, pp. 464–469.CrossRefGoogle Scholar
  20. 20.
    Wang, Y.-M., Robbrecht, E., Rouillard, A.P., et al, Formation and evolution of coronal holes following the emergence of active regions, Astrophys. J., 2010, vol. 715, no. 1, pp. 39–50.CrossRefGoogle Scholar

Copyright information

© Pleiades Publishing, Ltd. 2018

Authors and Affiliations

  1. 1.Crimean Astrophysical Observatory, Russian Academy of SciencesNauchnyRussia

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