Current sheets in the Sun’s corona

  • Eric Priest
Conference paper
Part of the Fluid Mechanics and Its Applications book series (FMIA, volume 71)


Current sheets play an important role in the Sun’s atmosphere, especially in coronal heating events and solar flares. They may form in response to motions of the magnetic footpoints in the solar surface or following a loss of equilibrium.

In two dimensions, X-type null points may collapse to current sheets, as described by nonlinear self-similar solutions and by complex-variable theory. Magnetic diffusion resolves the sheets and allows fast reconnection to take place. There are many ways in which such reconnection can occur, depending on the boundary conditions, including one family of almost-uniform regimes and another family of non-uniform regimes.

In three dimensions, nulls may also collapse to give a growing current along the spine or the fan of the null. (These are, respectively, isolated field lines or surfaces of field lines that approach or recede from the null point.) Dissipation can then occur by either spine reconnection or fan reconnection, or also by separator reconnection when the current concentrates along, respectively, the spine, the fan or a separator (which is a field line that links one null point to another).

Coronal heating may be produced by reconnection in the following ways: by converging photospheric motions at X-ray bright points; by binary reconnection when pairs of magnetic sources interact; by separator reconnection in complex fields due to tertiary flux interactions; by braiding of field lines; and by coronal tectonics heating at separatrix surfaces between intense flux tubes. Solar flares may occur when a magnetic catastrophe causes the slow eruption of a flux tube, which in turn drives the formation of a current sheet under the flux tube. As the sheet dissipates and reconnects, the overlying field lines holding down the flux tube are released so that rapid eruption and energy release can take place.


Field Line Current Sheet Solar Flare Flux Tube Null Point 
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  1. Bajer, K. 1990 PhD Thesis, Cambridge University.Google Scholar
  2. Bulanov, S.V. and Sakai, J. 1997 Magnetic collapse in incompressible plasma flows. J. Phys. Soc. Jap.66, 3477–3483.ADSCrossRefGoogle Scholar
  3. Bungey, T.N. and Priest, E.R. 1995 Current sheet configurations in potential and force-free fields. Astron. Astrophys.293, 215–224.ADSGoogle Scholar
  4. Galsgaard, K. and Nordlund, A. 1997a Heating and activity of the solar corona I. J. Geophys. Res.102, 231–248.ADSCrossRefGoogle Scholar
  5. Galsgaard, K. and Nordlund, A. 1997b Heating and activity of the solar corona I. J. Geophys. Res.101, 13445–13460.ADSCrossRefGoogle Scholar
  6. Galsgaard, K., Parnell, C.E. and Blaizot, J. 2000 Elementary heating events — magnetic interactions between two sources. Astron. Astrophys.362, 383–394.ADSGoogle Scholar
  7. Hornig, G. and Schindler, K. 1996 Magnetic topology and the problem of its invariant definition. Phys. Plasmas3, 781–791.CrossRefMathSciNetADSGoogle Scholar
  8. Longcope, D.W. 1996 Topology and current ribbons. Solar Phys.169, 91–121.CrossRefADSGoogle Scholar
  9. Moffatt, H.K. 1985 Magnetostatic equilibria and Euler flows of complex topology. J. Fluid Mech.159, 359–378.MathSciNetzbMATHADSCrossRefGoogle Scholar
  10. Parker, E.N. 1979 Cosmical Magnetic Fields, Clarendon Press, Oxford.Google Scholar
  11. Parnell, C.P., Smith, J., Neukirch, T. and Priest, E.R. 1996 Structure of 3D magnetic neutral points. Phys. Plasmas3, 759–770.CrossRefADSGoogle Scholar
  12. Priest, E.R. and Forbes, T.G. 2000 Magnetic Reconnection Camb. Univ. Press.Google Scholar
  13. Priest, E.R. and Schrijver, C.J. 1999 Aspects of 3D reconnection. Solar Phys.190, 1–24.CrossRefADSGoogle Scholar
  14. Priest, E.R. and Titov, V.S. 1996 Magnetic reconnection at 3D null points. Phil. Trans. Roy. Soc. Lond.354, 2951–2992.MathSciNetzbMATHADSCrossRefGoogle Scholar
  15. Priest, E.R., Titov, V.S. and Rickard, G.J. 1995 The formation of magnetic singularities by nonlinear time-dependent collapse of an X-type magnetic field. Phil. Trans. Roy. Soc. Lond. A.351, 1–37.ADSCrossRefzbMATHGoogle Scholar
  16. Somov, B.V. and Syrovatsky, S.I. 1976 Hydrodynamic plasma flow in a strong magnetic field. Proc. Lebedev Phys. Inst.74, 13–72.Google Scholar
  17. Titov, V.S. 1992 Calculating 2D potential fields with current sheets. Solar Phys.139, 401–404.CrossRefADSGoogle Scholar

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Eric Priest
    • 1
  1. 1.School of Mathematics and StatisticsUniversity of St AndrewsSt AndrewsScotland

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