A unified view of coronal loop contraction and oscillation in flares

Russell, A. J. B., Simoes, P. J. A. and Fletcher, L. (2015) A unified view of coronal loop contraction and oscillation in flares. Astronomy and Astrophysics, 581, A8. (doi:10.1051/0004-6361/201525746)

Russell, A. J. B., Simoes, P. J. A. and Fletcher, L. (2015) A unified view of coronal loop contraction and oscillation in flares. Astronomy and Astrophysics, 581, A8. (doi:10.1051/0004-6361/201525746)

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Abstract

Context: Transverse loop oscillations and loop contractions are commonly associated with solar flares, but the two types of motion have traditionally been regarded as separate phenomena. Aims: We present an observation of coronal loops contracting and oscillating following onset of a flare. We aim to explain why both behaviours are seen together and why only some of the loops oscillate. Methods: A time sequence of SDO/AIA 171 \r{A} images is analysed to identify positions of coronal loops following the onset of M6.4 flare SOL2012-03-09T03:53. We focus on five loops in particular, all of which contract during the flare, with three of them oscillating as well. A simple model is then developed for contraction and oscillation of a coronal loop. Results: We propose that coronal loop contractions and oscillations can occur in a single response to removal of magnetic energy from the corona. Our model reproduces the various types of loop motion observed and explains why the highest loops oscillate during their contraction while no oscillation is detected for the shortest contracting loops. The proposed framework suggests that loop motions can be used as a diagnostic for the removal of coronal magnetic energy by flares, while rapid decrease of coronal magnetic energy is a newly-identified excitation mechanism for transverse loop oscillations.

Item Type:Articles
Keywords:Astrophysics - Solar and Stellar Astrophysics
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Simoes, Dr Paulo and Fletcher, Professor Lyndsay and Russell, Dr Alexander
Authors: Russell, A. J. B., Simoes, P. J. A., and Fletcher, L.
Subjects:Q Science > QB Astronomy
Q Science > QC Physics
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Astronomy and Astrophysics
Publisher:EDP Sciences
ISSN:0004-6361
ISSN (Online):1432-0746
Copyright Holders:Copyright © 2015 EDP Sciences
First Published:First published in Astronomy and Astrophysics 581:A8
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher.
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
595181Chromospheric Flares: Observations, Models and Archives (CHROMA)Lyndsay FletcherEuropean Commission (EC)606862P&A - PHYSICS & ASTRONOMY
542081Rolling Programme in Solar and Plasma AstrophysicsLyndsay FletcherScience & Technologies Facilities Council (STFC)ST/I001808/1P&A - PHYSICS & ASTRONOMY
631581Consolidated grant in solar and astrophysical plasmasLyndsay FletcherScience & Technologies Facilities Council (STFC)ST/L000741/1S&E P&A - PHYSICS & ASTRONOMY