Filamentary structure on the Sun from the magnetic Rayleigh–Taylor instability


Magnetic flux emerges from the solar surface as dark filaments connecting small sunspots with opposite polarities1,2,3. The regions around the dark filaments are often bright in X-rays and are associated with jets4,5,6. This implies plasma heating and acceleration, which are important for coronal heating. Previous two-dimensional simulations of such regions showed that magnetic reconnection between the coronal magnetic field and the emerging flux produced X-ray jets and flares, but left unresolved the origin of filamentary structure and the intermittent nature of the heating. Here we report three-dimensional simulations of emerging flux showing that the filamentary structure arises spontaneously from the magnetic Rayleigh–Taylor instability7,8, contrary to the previous view that the dark filaments are isolated bundles of magnetic field that rise from the photosphere carrying the dense gas9,10,11. As a result of the magnetic Rayleigh–Taylor instability, thin current sheets are formed in the emerging flux, and magnetic reconnection occurs between emerging flux and the pre-existing coronal field in a spatially intermittent way. This explains naturally the intermittent nature of coronal heating and the patchy brightenings in solar flares.

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Figure 1: Three-dimensional visualization of the simulation result at t = 2,500 s.
Figure 2: Temporal evolution of the mass density (colour), velocity (arrows) and resistivity (green contour) on a yz plane near the reconnection points.
Figure 3: Comparison of the simulation result and observations.
Figure 4: Three-dimensional visualization of the simulation result, showing the structure of plasma flows from reconnection points.


  1. 1

    Bruzek, A. On arch-filament system in spotgroups. Sol. Phys 2, 451–461 (1967)

    ADS  Article  Google Scholar 

  2. 2

    Zirin, H. Fine structure of solar magnetic fields. Sol. Phys. 22, 34–48 (1972)

    ADS  Article  Google Scholar 

  3. 3

    Frazier, E. N. The magnetic structure of arch filament system. Sol. Phys. 26, 130–141 (1972)

    ADS  Article  Google Scholar 

  4. 4

    Golub, L., Rosner, R., Vaiana, G. S. & Weiss, N. O. Solar magnetic fields: the generation of emerging flux. Astrophys. J. 243, 309–316 (1981)

    ADS  Article  Google Scholar 

  5. 5

    Yoshimura, K. & Kurokawa, H. Causal relations between Hα loop emergences and soft X-ray brightenings. Astrophys. J. 517, 964–976 (1999)

    ADS  Article  Google Scholar 

  6. 6

    Shibata, K. et al. Observations of X-ray jets with the YOHKOH Soft X-ray Telescope. Publ. Astron. Soc. Jpn. 44, L173–L179 (1992)

    ADS  Google Scholar 

  7. 7

    Sharp, D. H. An overview of Rayleigh–Taylor instability. Physica 12D, 3–18 (1984)

    ADS  MATH  Google Scholar 

  8. 8

    Cattaneo, F. & Hughes, D. H. The nonlinear break up of a magnetic layer: instability to interchange modes. J. Fluid Mech. 196, 323–344 (1988)

    ADS  Article  Google Scholar 

  9. 9

    Zwaan, C. The emergence of magnetic flux. Sol. Phys. 100, 397–414 (1985)

    ADS  CAS  Article  Google Scholar 

  10. 10

    Shibata, K. et al. Nonlinear Parker instability of isolated magnetic flux in a plasma. Astrophys. J. 338, 471–492 (1989)

    ADS  Article  Google Scholar 

  11. 11

    Matsumoto, R., Tajima, T., Shibata, K. & Kaisig, M. Three-dimensional magnetohydrodynamics of the emerging magnetic flux in the solar atmosphere. Astrophys. J. 414, 357–371 (1993)

    ADS  Article  Google Scholar 

  12. 12

    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)

    ADS  CAS  Article  Google Scholar 

  13. 13

    Yokoyama, T. & Shibata, K. Numerical simulation of solar coronal X-ray jets based on the magnetic reconnection model. Publ. Astron. Soc. Jpn. 48, 353–376 (1996)

    ADS  Article  Google Scholar 

  14. 14

    Ugai, M. Computer studies on development of the fast reconnection mechanism for different resistivity models. Phys. Fluids B. 4, 2953–2963 (1992)

    ADS  Article  Google Scholar 

  15. 15

    Yokoyama, T. & Shibata, K. What is the condition for fast magnetic reconnection? Astrophys. J. 436, L197–L200 (1994)

    ADS  Article  Google Scholar 

  16. 16

    Miyagoshi, T. & Yokoyama, T. Magnetohydrodynamic numerical simulations of solar X-ray jets based on the magnetic reconnection model that includes chromospheric evaporation. Astrophys. J. 593, L133–L136 (2003)

    ADS  CAS  Article  Google Scholar 

  17. 17

    Solanki, S. K. et al. Three-dimensional magnetic field topology in a region of solar coronal heating. Nature 425, 692–695 (2003)

    ADS  CAS  Article  Google Scholar 

  18. 18

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

    ADS  Article  Google Scholar 

  19. 19

    Galsgaad, K. & Nordlund, A. Heating and activity of the solar corona. 1. Boundary shearing of an initially homogeneous magnetic field. J. Geophys. Res. 101, 13445–13460 (1996)

    ADS  Article  Google Scholar 

  20. 20

    Karpen, J. T., Antiochos, S. K. & DeVore, C. R. Reconnection-driven current filamentation in solar arcades. Astrophys. J. 460, L73–L76 (1996)

    ADS  Article  Google Scholar 

  21. 21

    Hachisu, I., Matsuda, T., Nomoto, K. & Shigeyama, T. Nonlinear growth of Rayleigh–Taylor instabilities and mixing in SN 1987A. Astrophys. J. 358, L57–L61 (1990)

    ADS  CAS  Article  Google Scholar 

  22. 22

    Ugai, M. & Shimizu, T. Computer studies on the spontaneous fast reconnection mechanism in three dimensions. Phys. Plasmas 3, 853–862 (1996)

    ADS  CAS  Article  Google Scholar 

  23. 23

    Kitahara, T. & Kurokawa, H. High-resolution observation and detailed photometry of a great Hα two-ribbon flare. Sol. Phys 125, 321–332 (1990)

    ADS  CAS  Article  Google Scholar 

  24. 24

    Innes, D. E., McKenzie, D. E. & Wang, T. SUMER spectral observations of post-flare supra-arcade inflows. Sol. Phys. 217, 247–265 (2003)

    ADS  CAS  Article  Google Scholar 

  25. 25

    Asai, A., Yokoyama, T., Shimojo, M. & Shibata, K. Downflow motions associated with impulsive nonthermal emissions observed in the 2002 July 23 solar flare. Astrophys. J. 605, L77–L80 (2004)

    ADS  CAS  Article  Google Scholar 

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The authors thank N. O. Weiss, A. Asai and D. H. Brooks for comments. Use of TRACE data is acknowledged. This work was supported by the Japan–UK Cooperation Science Program of the JSPS (Principal investigators K.S. and N. O. Weiss) and a Grant-in-Aid for the 21st Century COE ‘Centre for Diversity and Universality in Physics’ from MEXT, Japan. The numerical computation was performed on the Earth Simulator.

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Correspondence to Hiroaki Isobe.

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Isobe, H., Miyagoshi, T., Shibata, K. et al. Filamentary structure on the Sun from the magnetic Rayleigh–Taylor instability. Nature 434, 478–481 (2005).

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