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A substantial amount of hidden magnetic energy in the quiet Sun

Nature volume 430, pages 326–329 (2004)Cite this article

Abstract

Deciphering and understanding the small-scale magnetic activity of the quiet solar photosphere should help to solve many of the key problems of solar and stellar physics, such as the magnetic coupling to the outer atmosphere and the coronal heating1,2,3. At present, we can see only ∼1 per cent of the complex magnetism of the quiet Sun1,4,5,6,7, which highlights the need to develop a reliable way to investigate the remaining 99 per cent. Here we report three-dimensional radiative transfer modelling of scattering polarization in atomic and molecular lines that indicates the presence of hidden, mixed-polarity fields on subresolution scales. Combining this modelling with recent observational data8,9,10,11, we find a ubiquitous tangled magnetic field with an average strength of ∼130 G, which is much stronger in the intergranular regions of solar surface convection than in the granular regions. So the average magnetic energy density in the quiet solar photosphere is at least two orders of magnitude greater than that derived from simplistic one-dimensional investigations12,13, and sufficient to balance radiative energy losses from the solar chromosphere.

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Figure 1: Spectropolarimetric observations versus 3D modelling of the Hanle effect.
Figure 2: Evidence for a ‘turbulent’ field organized at the spatial scales of the solar granulation pattern.

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Acknowledgements

We thank F. Kneer, E. Landi Degl'Innocenti and F. Moreno-Insertis for scientific discussions. We are also grateful to P. Fabiani Bendicho for help with the numerical solution of the 3D radiative transfer equation. This research was supported by the Spanish Plan Nacional de Astronomía y Astrofísica and by the European Commission via the INTAS programme and the Solar Magnetism Network.

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Authors and Affiliations

  1. Instituto de Astrofísica de Canarias, E-38205, La Laguna, Tenerife, Spain

    J. Trujillo Bueno & A. Asensio Ramos

  2. Consejo Superior de Investigaciones Científicas, E-28006, Madrid, Spain

    J. Trujillo Bueno

  3. Main Astronomical Observatory, National Academy of Sciences, Zabolotnogo 27, 03680, Kyiv, Ukraine

    N. Shchukina

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  1. J. Trujillo Bueno
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Correspondence to J. Trujillo Bueno.

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Bueno, J., Shchukina, N. & Ramos, A. A substantial amount of hidden magnetic energy in the quiet Sun. Nature 430, 326–329 (2004). https://doi.org/10.1038/nature02669

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