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Direct evidence that twisted flux tube emergence creates solar active regions

MacTaggart, D.; Prior, C.; Raphaldini, B.; Romano, P.; Guglielmino, S.L.

Direct evidence that twisted flux tube emergence creates solar active regions Thumbnail


D. MacTaggart

B. Raphaldini

P. Romano

S.L. Guglielmino


The magnetic nature of the formation of solar active regions lies at the heart of understanding solar activity and, in particular, solar eruptions. A widespread model, used in many theoretical studies, simulations and the interpretation of observations, is that the basic structure of an active region is created by the emergence of a large tube of pre-twisted magnetic field. Despite plausible reasons and the availability of various proxies suggesting the accuracy of this model, there has not yet been a methodology that can clearly and directly identify the emergence of large pre-twisted magnetic flux tubes. Here, we present a clear signature of the emergence of pre-twisted magnetic flux tubes by investigating a robust topological quantity, called magnetic winding, in solar observations. This quantity detects the emerging magnetic topology despite the significant deformation experienced by the emerging magnetic field. Magnetic winding complements existing measures, such as magnetic helicity, by providing distinct information about field line topology, thus allowing for the direct identification of emerging twisted magnetic flux tubes.


MacTaggart, D., Prior, C., Raphaldini, B., Romano, P., & Guglielmino, S. (2021). Direct evidence that twisted flux tube emergence creates solar active regions. Nature Communications, 12(1),

Journal Article Type Article
Acceptance Date Oct 28, 2021
Online Publication Date Nov 16, 2021
Publication Date 2021
Deposit Date Feb 1, 2022
Publicly Available Date Feb 1, 2022
Journal Nature Communications
Electronic ISSN 2041-1723
Publisher Nature Research
Peer Reviewed Peer Reviewed
Volume 12
Issue 1


Published Journal Article (1.6 Mb)

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