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Estimating the Rate of Field Line Braiding in the Solar Corona by Photospheric Flows

Candelaresi, S.; Pontin, D.I.; Yeates, A.R.; Bushby, P.J.; Hornig, G.

Estimating the Rate of Field Line Braiding in the Solar Corona by Photospheric Flows Thumbnail


Authors

S. Candelaresi

D.I. Pontin

P.J. Bushby

G. Hornig



Abstract

In this paper, we seek to understand the timescale in which the photospheric motions on the Sun braid coronal magnetic field lines. This is a crucial ingredient for determining the viability of the braiding mechanism for explaining the high temperatures observed in the corona. We study the topological complexity induced in the coronal magnetic field, primarily using plasma motions extracted from magneto-convection simulations. This topological complexity is quantified using the field line winding, finite time topological entropy (FTTE), and passive scalar mixing. With these measures, we contrast mixing efficiencies of the magneto-convection simulation, a benchmark flow known as a "blinking vortex", and finally photospheric flows inferred from sequences of observed magnetograms using local correlation tracking. While the highly resolved magneto-convection simulations induce a strong degree of field line winding and FTTE, the values obtained from the observations from the plage region are around an order of magnitude smaller. This behavior is carried over to the FTTE. Nevertheless, the results suggest that the photospheric motions induce complex tangling of the coronal field on a timescale of hours.

Citation

Candelaresi, S., Pontin, D., Yeates, A., Bushby, P., & Hornig, G. (2018). Estimating the Rate of Field Line Braiding in the Solar Corona by Photospheric Flows. Astrophysical Journal, 864(2), Article 157. https://doi.org/10.3847/1538-4357/aad8bc

Journal Article Type Article
Acceptance Date Jul 25, 2018
Online Publication Date Sep 12, 2018
Publication Date Sep 12, 2018
Deposit Date Sep 12, 2018
Publicly Available Date Mar 29, 2024
Journal Astrophysical Journal
Print ISSN 0004-637X
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 864
Issue 2
Article Number 157
DOI https://doi.org/10.3847/1538-4357/aad8bc
Related Public URLs https://arxiv.org/abs/1805.03010

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Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/

Copyright Statement
Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.




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