Skip to main content

Research Repository

Advanced Search

Computation of Winding-Based Magnetic Helicity and Magnetic Winding Density for SHARP Magnetograms in Spherical Coordinates

Xiao, Daining; Prior, Christopher B.; Yeates, Anthony R.

Computation of Winding-Based Magnetic Helicity and Magnetic Winding Density for SHARP Magnetograms in Spherical Coordinates Thumbnail


Authors

Daining Xiao daining.xiao@durham.ac.uk
PGR Student Doctor of Philosophy



Abstract

Magnetic helicity has been used widely in the analysis and modelling of solar active regions. However, it is difficult to evaluate and interpret helicity in spherical geometry since coronal magnetic fields are rooted in the photosphere and helicity is susceptible to gauge choices. Recent work extended a geometrical definition of helicity from Cartesian to spherical domains, by interpreting helicity as the average, flux-weighted pairwise winding of magnetic-field lines. In this paper, by adopting the winding-based definition of helicity, we compute helicity and winding in spherical coordinates for SHARP (Spaceweather HMI Active Region Patches) magnetograms. This is compared with results obtained in Cartesian coordinates to quantitatively investigate the effect of spherical geometry. We find that the Cartesian approximations remain mostly valid, but for active regions with large spatial extents or strong field strengths (usually leading to flares and coronal mass ejections) there are significant deviations due to surface curvature that must be accounted for.

Citation

Xiao, D., Prior, C. B., & Yeates, A. R. (2023). Computation of Winding-Based Magnetic Helicity and Magnetic Winding Density for SHARP Magnetograms in Spherical Coordinates. Solar Physics, 298(10), Article 116. https://doi.org/10.1007/s11207-023-02211-9

Journal Article Type Article
Acceptance Date Sep 20, 2023
Online Publication Date Oct 6, 2023
Publication Date 2023-10
Deposit Date Oct 9, 2023
Publicly Available Date Oct 9, 2023
Journal Solar Physics
Print ISSN 0038-0938
Electronic ISSN 1573-093X
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 298
Issue 10
Article Number 116
DOI https://doi.org/10.1007/s11207-023-02211-9
Keywords Magnetic fields, Active regions, Magnetohydrodynamics, Helicity
Public URL https://durham-repository.worktribe.com/output/1787791

Files

Published Journal Article (8.1 Mb)
PDF

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

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

Copyright Statement
This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.





You might also like



Downloadable Citations