The pre-penumbral magnetic canopy in the solar atmosphere

MacTaggart, D. , Guglielmino, S. L. and Zuccarello, F. (2016) The pre-penumbral magnetic canopy in the solar atmosphere. Astrophysical Journal Letters, 831(1), L4. (doi: 10.3847/2041-8205/831/1/L4)

130317.pdf - Accepted Version



Penumbrae are the manifestation of magnetoconvection in highly inclined (to the vertical direction) magnetic field. The penumbra of a sunspot tends to form, initially, along the arc of the umbra antipodal to the main region of flux emergence. The question of how highly inclined magnetic field can concentrate along the antipodal curves of umbrae, at least initially, remains to be answered. Previous observational studies have suggested the existence of some form of overlying magnetic canopy which acts as the progenitor for penumbrae. We propose that such overlying magnetic canopies are a consequence of how the magnetic field emerges into the atmosphere and are, therefore, part of the emerging region. We show, through simulations of twisted flux tube emergence, that canopies of highly inclined magnetic field form preferentially at the required locations above the photosphere.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Mactaggart, Dr David
Authors: MacTaggart, D., Guglielmino, S. L., and Zuccarello, F.
College/School:College of Science and Engineering > School of Mathematics and Statistics > Mathematics
Journal Name:Astrophysical Journal Letters
Publisher:IOP Publishing
ISSN (Online):2041-8213
Published Online:24 October 2016
Copyright Holders:Copyright © 2016 The American Astronomical Society
First Published:First published in Astrophysical Journal Letters 831(1):L4
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
Related URLs:

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
716211The evolution of magnetic helicity in the dynamic solar atmosphereDavid MactaggartThe Carnegie Trust for the Universities of Scotland (CARNEGIE)70323M&S - MATHEMATICS