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Three-dimensional magnetic field topology in a region of solar coronal heating

Nature volume 425, pages 692–695 (2003)Cite this article

Abstract

Flares and X-ray jets on the Sun arise in active regions where magnetic flux emerges from the solar interior amd interacts with the ambient magnetic field1,2. The interactions are believed to occur in electric current sheets separating regions of opposite magnetic polarity. The current sheets located in the corona or upper chromosphere have long been thought to act as an important source of coronal heating3,4,5,6, requiring their location in the corona or upper chromosphere. The dynamics and energetics of these sheets are governed by a complex magnetic field structure that, until now, has been difficult to measure. Here we report the determination of the full magnetic vector in an interaction region near the base of the solar corona. The observations reveal two magnetic features that characterize young active regions on the Sun: a set of rising magnetic loops and a tangential discontinuity of the magnetic field direction, the latter being the observational signature of an electric current sheet. This provides strong support for coronal heating models based on the dissipation of magnetic energy at current sheets.

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Figure 1: Atmospheric parameters of an emerging flux region (NOAA active region 9451, 33°W, 22°S).
Figure 2: Magnetic and velocity field parameters obtained from the He triplet along ‘Cut 1’ in Fig. 1.
Figure 3: Reconstructed magnetic loops in the emerging flux region.
Figure 4: Representation of the electric current sheet (See ‘Region 2’ in Fig. 1 for the location within the full scanned region).

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References

  1. Yokoyama, T. & Shibata, K. Magnetic reconnection as the origin of X-ray jets and H-alpha surges in the Sun. Nature 375, 42–44 (1995)

    Article  CAS  Google Scholar 

  2. Lites, B. W., Skumaniah, A. & Martínez Pillet, V. Vector magnetic fields of emerging solar flux. I. Properties at the site of emergence. Astron. Astrophys. 333, 1053–1068 (1998)

    Google Scholar 

  3. Parker, E. N. Magnetic neutral sheets in evolving fields—Part One—General theory. Astrophys. J. 264, 635–641 (1983)

    Article  Google Scholar 

  4. Parker, E. N. Magnetic neural sheets in evolving fields—Part Two—Formation of the solar corona. Astrophys. J. 264, 642–647 (1983)

    Article  Google Scholar 

  5. Parker, E. N. Nanoflares and the solar X-ray corona. Astrophys. J. 330, 474–479 (1988)

    Article  Google Scholar 

  6. Ulmschneider, P., Priest, E. R. & Rosner, R. (eds) Mechanism of Chromospheric and Coronal Heating Ch. 4 (Springer, Berlin/Heidelberg/New York, 1991)

  7. Mártinez Pillet, V. et al. in ASP Conf. Ser. 183. High Resolution Solar Physics: Theory, Observation, and Techniques 264 (Astronomical Society of the Pacific, San Francisco, California, 1999)

    Google Scholar 

  8. Harvey, J. & Hall, D. in IAU Symp. 43. Solar Magnetic Fields (ed. Howard, R.) 279–288 (Dordrecht, Reidel, 1971)

    Book  Google Scholar 

  9. Penn, M. J. & Kuhn, J. R. Imaging spectropolarimetry of the He I 1083 nanometer line in a flaring solar active region. Astrophys. J. 441, L51–L54 (1995)

    Article  CAS  Google Scholar 

  10. Rüedi, I., Solanki, S. K. & Livingston, W. C. Infrared lines as probes of solar magnetic features. X. He I 10830A as a diagnostic of chromospheric magnetic fields. Astron. Astrophys. 293, 252–262 (1995)

    Google Scholar 

  11. Rüedi, I., Keller, C. U. & Solanki, S. K. Measurements of the full Stokes vector of He I 10830 A. Sol. Phys. 164, 265–275 (1996)

    Article  Google Scholar 

  12. Handy, B. N. et al. The transition region and coronal explorer. Sol. Phys. 187, 229–260 (1999)

    Article  CAS  Google Scholar 

  13. Schmidt, W., Muglach, K. & Knölker, M. Free-fall downflow observed in He I 1083.0 nanometers and Hβ. Astrophys. J. 544, 567–571 (2000)

    Article  Google Scholar 

  14. Zirin, H. & Wang, H. Narrow lanes of transverse magnetic field in sunspots. Nature 363, 426–428 (1993)

    Article  Google Scholar 

  15. Galsgaard, K. & Longbottom, A. W. Formation of solar prominences by flux convergence. Astrophys. J. 510, 444–459 (1999)

    Article  Google Scholar 

  16. Gudiksen, B. V. & Nordlund, Å. Bulk heating and slender magnetic loops in the solar corona. Astrophys. J. 572, L113–L116 (2002)

    Article  CAS  Google Scholar 

  17. Ruiz Cobo, B. & del Toro Iniesta, J. C. Inversion of Stokes profiles. Astrophys. J. 398, 375–385 (1992)

    Article  Google Scholar 

  18. Frutiger, C., Solanki, S. K., Fligge, M. & Bruls, J. H. M. J. Properties of the solar granulation obtained from the inversion of low spatial resolution spectra. Astron. Astrophys. 358, 1109–1121 (2000)

    Google Scholar 

  19. Kurucz, R. L. ‘Finding’ the ‘Missing’ solar ultraviolet opacity. Rev. Mexicana Astron. Astrofis. 23, 181–186 (1992)

    CAS  Google Scholar 

  20. Avrett, E. H., Fontenla, J. M. & Loeser, R. in IAU Symp. 154. Infrared Solar Physics (ed. Rabin, D. M.) 35–47 (Kluwer Academic, Dordrecht, 1994)

    Book  Google Scholar 

  21. Giovanelli, R. G. & Hall, D. The helium 10830 A line in the undisturbed chromosphere. Sol. Phys. 52, 211–228 (1977)

    Article  CAS  Google Scholar 

  22. Rachkowsky, D. N. The reduction for anomalous dispersion in the theory of the absorption line formation in a magnetic field [in Russian]. Izv. Krym. Astrofiz. Obs. 37, 56–61 (1967)

    Google Scholar 

  23. Trujillo Bueno, J., Landi Degl'Innocenti, E., Collados, M., Merenda, L. & Manso Sainz, R. Selective absorption processes as the origin of puzzling spectral line polarization from the Sun. Nature 415, 403–406 (2002)

    Article  CAS  Google Scholar 

  24. Lagg, A., Woch, J., Krupp, N. & Solanki, S. K. Retrieval of the full magnetic vector with the He I multiplet at 1083 nm. Astron. Astrophys. (submitted)

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Acknowledgements

M.C. acknowledges support from the Spanish Ministerio de Ciencia y Tecnologia. We thank the Kiepenheuer Institut in Freiburg, Germany, for observing support.

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Authors and Affiliations

  1. Max-Planck-Institut für Aeronomie, 37191, Katlenburg-Lindau, Germany

    S. K. Solanki, A. Lagg, J. Woch & N. Krupp

  2. Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain

    M. Collados

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Correspondence to S. K. Solanki.

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Solanki, S., Lagg, A., Woch, J. et al. Three-dimensional magnetic field topology in a region of solar coronal heating. Nature 425, 692–695 (2003). https://doi.org/10.1038/nature02035

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