Letter | Published:

Magnetic tornadoes as energy channels into the solar corona

Nature volume 486, pages 505508 (28 June 2012) | Download Citation



Heating the outer layers of the magnetically quiet solar atmosphere to more than one million kelvin and accelerating the solar wind requires an energy flux of approximately 100 to 300 watts per square metre1,2,3,4,5,6, but how this energy is transferred and dissipated there is a puzzle and several alternative solutions have been proposed. Braiding and twisting of magnetic field structures, which is caused by the convective flows at the solar surface, was suggested as an efficient mechanism for atmospheric heating7. Convectively driven vortex flows that harbour magnetic fields are observed8,9,10 to be abundant in the photosphere (the visible surface of the Sun). Recently, corresponding swirling motions have been discovered11 in the chromosphere, the atmospheric layer sandwiched between the photosphere and the corona. Here we report the imprints of these chromospheric swirls in the transition region and low corona, and identify them as observational signatures of rapidly rotating magnetic structures. These ubiquitous structures, which resemble super-tornadoes under solar conditions, reach from the convection zone into the upper solar atmosphere and provide an alternative mechanism for channelling energy from the lower into the upper solar atmosphere.

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We acknowledge discussions with R. Hammer, M. Carlsson, V. Hansteen and S. McIntosh. M. Carlsson and B. Gudiksen are thanked for providing BIFROST simulation data and input on its analysis. This work was supported by the Research Council of Norway including computing time through the Programme for Supercomputing (Notur). R.E. acknowledges M. Kéray for encouragement and is also grateful to the NSF, Hungary. R.E. and V.F. also acknowledge the support received from the Science and Technology Facilities, UK. The Swedish 1-m Solar Telescope is operated on the island of La Palma by the Institute for Solar Physics of the Royal Swedish Academy of Sciences in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. We thank the Computational Information Systems Laboratory at the National Center for Atmospheric Research for providing the VAPOR analysis tool.

Author information


  1. Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, N-0315 Oslo, Norway

    • Sven Wedemeyer-Böhm
    • , Eamon Scullion
    •  & Luc Rouppe van der Voort
  2. Center of Mathematics for Applications, University of Oslo, PO Box 1053 Blindern, N-0316 Oslo, Norway

    • Sven Wedemeyer-Böhm
  3. Kiepenheuer Institute for Solar Physics, Schöneckstrasse 6–7, D-79104 Freiburg, Germany

    • Oskar Steiner
  4. Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden

    • Jaime de la Cruz Rodriguez
  5. Solar Physics and Space Plasma Research Centre, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK

    • Viktor Fedun
    •  & Robert Erdélyi


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S.W.-B. and E.S. produced and analysed the data with help from all authors. O.S., V.F. and R.E. gave advice on the data analysis, aspects of the physical interpretation and the applied numerical methods. J.d.l.C.R. and L.R.v.d.V. contributed to the collection and preparation of the observational data and its comparison with numerical data. All authors discussed the results and contributed to and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Sven Wedemeyer-Böhm.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    This file contains Supplementary Table 1, which outlines the properties of all 14 swirls; Supplementary Figures 1-3, which illustrate the expansion of the magnetic field in a tornado into the solar corona, the comparison of an observed and a simulated swirl, and the related transport of energy; and Supplementary Notes which describe the derivations of the average Poynting flux.


  1. 1.

    Supplementary Movie 1

    This movie file shows a brief overview of the SST/CRISP (CRisp Imaging SpectroPolarimeter) data accumulated in this observational study of chromospheric swirls. The detection and properties (Doppler-shift structure and evolution to hotter channels as observed with the SDO) attributed to swirl #1 follows the overview.

  2. 2.

    Supplementary Movie 2

    This movie file shows the temporal evolution of all of the 14 swirls detected. Each swirl was recorded during a 55 min observing run on 8th May 2011.

  3. 3.

    Supplementary Movie 3

    This movie file outlines the results of a numerical simulation (CO5BOLD) of a solar magnetic tornado. The physical process describing the formation of the magnetic tornado is presented. The evolution of the flow field within the magnetic tornado through to the upper chromosphere is shown, thus, explaining its swirling nature.

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