Allcock, M. and Erdélyi, R. (2017) Magnetohydrodynamic Waves in an Asymmetric Magnetic Slab. Solar Physics, 292 (2). 35. ISSN 0038-0938
Abstract
Analytical models of solar atmospheric magnetic structures have been crucial for our understanding of magnetohydrodynamic (MHD) wave behaviour and in the development of the field of solar magneto-seismology. Here, an analytical approach is used to derive the dispersion relation for MHD waves in a magnetic slab of homogeneous plasma enclosed on its two sides by non-magnetic, semi-infinite plasma with different densities and temperatures. This generalises the classic magnetic slab model, which is symmetric about the slab. The dispersion relation, unlike that governing a symmetric slab, cannot be decoupled into the well-known sausage and kink modes, i.e. the modes have mixed properties. The eigenmodes of an asymmetric magnetic slab are better labelled as quasi-sausage and quasi-kink modes. Given that the solar atmosphere is highly inhomogeneous, this has implications for MHD mode identification in a range of solar structures. A parametric analysis of how the mode properties (in particular the phase speed, eigenfrequencies, and amplitudes) vary in terms of the introduced asymmetry is conducted. In particular, avoided crossings occur between quasi-sausage and quasi-kink surface modes, allowing modes to adopt different properties for different parameters in the external region.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Author(s) 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. |
Keywords: | Coronal seismology; Magnetic fields, photosphere; Waves, magnetohydrodynamic; Waves, modes |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > School of Mathematics and Statistics (Sheffield) |
Funding Information: | Funder Grant number SCIENCE AND TECHNOLOGY FACILITIES COUNCIL ST/L006316/1 SCIENCE AND TECHNOLOGY FACILITIES COUNCIL ST/M000826/1 ROYAL SOCIETY IE141493 SCIENCE AND TECHNOLOGY FACILITIES COUNCIL ST/G002207/1 EUROPEAN COMMISSION - HORIZON 2020 PROGRESS - 637302 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 28 Feb 2017 14:01 |
Last Modified: | 28 Feb 2017 14:01 |
Published Version: | https://doi.org/10.1007/s11207-017-1054-y |
Status: | Published |
Publisher: | Springer Verlag |
Refereed: | Yes |
Identification Number: | 10.1007/s11207-017-1054-y |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:112535 |