Gordovskyy, M., Browning, P. K. and Kontar, E. P. (2017) Polarisation of microwave emission from reconnecting twisted coronal loops. Astronomy and Astrophysics, 604, A116. (doi: 10.1051/0004-6361/201629334)
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Abstract
Context: Magnetic reconnection and particle acceleration due to the kink instability in twisted coronal loops can be a viable scenario for confined solar flares. Detailed investigation of this phenomenon requires reliable methods for observational detection of magnetic twist in solar flares, which may not be possible solely through extreme UV and soft X-ray thermal emission. Polarisation of microwave emission in flaring loops can be used as one of the detection criteria. Aims: The aim of this study is to investigate the effect of magnetic twist in flaring coronal loops on the polarisation of gyro-synchrotron microwave (GSMW) emission, and determine whether it could provide a means for magnetic twist detection. Methods: We consider time-dependent magnetohydrodynamic and test-particle models developed using the LARE3D and GCA codes to investigate twisted coronal loops that relax after kink instability. Synthetic GSMW emission maps (I and V Stokes components) are calculated using GX simulator. Results: It is found that flaring twisted coronal loops produce GSMW radiation with a gradient of circular polarisation across the loop. However, these patterns may be visible only for a relatively short period of time owing to fast magnetic reconfiguration after the instability. Their visibility also depends on the orientation and position of the loop on the solar disk. Typically, it would be difficult to see these characteristic polarisation patterns in a twisted loop seen from the top (i.e. close to the centre of the solar disk), but easier in a twisted loop seen from the side (i.e. observed very close to the limb).
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Kontar, Professor Eduard |
Authors: | Gordovskyy, M., Browning, P. K., and Kontar, E. P. |
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 |
Published Online: | 22 August 2017 |
Copyright Holders: | Copyright © 2017 EDP Sciences |
First Published: | First published in Astronomy and Astrophysics 604:A116 |
Publisher Policy: | Reproduced in accordance with the copyright policy of the publisher |
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