Williamson, A. and Erdélyi, R. (2016) Linear MHD Wave Propagation in Time-Dependent Flux Tube: III. Leaky Waves in Zero-Beta Plasma. Solar Physics, 291 (1). pp. 175-185. ISSN 0038-0938
Abstract
In this article, we evaluate the time-dependent wave properties and the damping rate of propagating fast magneto-hydrodynamic (MHD) waves when energy leakage into a magnetised atmosphere is considered. By considering a cold plasma, initial investigations into the evolution of MHD wave damping through this energy leakage will take place. The time-dependent governing equations have been derived previously in Williamson and Erdélyi (2014a, Solar Phys.289, 899 – 909) and are now solved when the assumption of evanescent wave propagation in the outside of the waveguide is relaxed. The dispersion relation for leaky waves applicable to a straight magnetic field is determined in both an arbitrary tube and a thin-tube approximation. By analytically solving the dispersion relation in the thin-tube approximation, the explicit expressions for the temporal evolution of the dynamic frequency and wavenumber are determined. The damping rate is, then, obtained from the dispersion relation and is shown to decrease as the density ratio increases. By comparing the decrease in damping rate to the increase in damping for a stationary system, as shown, we aim to point out that energy leakage may not be as efficient a damping mechanism as previously thought.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015, The Author(s). 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: | Magnetohydrodynamics; Waves; 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) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 04 Nov 2016 10:31 |
Last Modified: | 04 Nov 2016 10:31 |
Published Version: | http://dx.doi.org/10.1007/s11207-015-0802-0 |
Status: | Published |
Publisher: | Springer Verlag (Germany) |
Refereed: | Yes |
Identification Number: | 10.1007/s11207-015-0802-0 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:106435 |