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The global distribution of magnetic helicity in the solar corona

Yeates, A.R.; Hornig, G.

The global distribution of magnetic helicity in the solar corona Thumbnail


Authors

G. Hornig



Abstract

By defining an appropriate field line helicity, we apply the powerful concept of magnetic helicity to the problem of global magnetic field evolution in the Sun's corona. As an ideal-magnetohydrodynamic invariant, the field line helicity is a meaningful measure of how magnetic helicity is distributed within the coronal volume. It may be interpreted, for each magnetic field line, as a magnetic flux linking with that field line. Using magneto-frictional simulations, we investigate how field line helicity evolves in the non-potential corona as a result of shearing by large-scale motions on the solar surface. On open magnetic field lines, the helicity injected by the Sun is largely output to the solar wind, provided that the coronal relaxation is sufficiently fast. But on closed magnetic field lines, helicity is able to build up. We find that the field line helicity is non-uniformly distributed, and is highly concentrated in twisted magnetic flux ropes. Eruption of these flux ropes is shown to lead to sudden bursts of helicity output, in contrast to the steady flux along the open magnetic field lines.

Citation

Yeates, A., & Hornig, G. (2016). The global distribution of magnetic helicity in the solar corona. Astronomy & Astrophysics, 594, Article A98. https://doi.org/10.1051/0004-6361/201629122

Journal Article Type Article
Acceptance Date Aug 5, 2016
Online Publication Date Oct 19, 2016
Publication Date Oct 19, 2016
Deposit Date Aug 30, 2016
Publicly Available Date Aug 31, 2016
Journal Astronomy and astrophysics.
Print ISSN 0004-6361
Electronic ISSN 1432-0746
Publisher EDP Sciences
Peer Reviewed Peer Reviewed
Volume 594
Article Number A98
DOI https://doi.org/10.1051/0004-6361/201629122
Related Public URLs http://arxiv.org/abs/1606.06863

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Accepted Journal Article (2.1 Mb)
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Copyright Statement
Reproduced with permission from Astronomy & Astrophysics, © ESO 2016





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