Skirvin, S.J., Fedun, V. orcid.org/0000-0002-0893-7346, Silva, S.S.A. et al. (1 more author) (2022) II. The effect of axisymmetric and spatially varying equilibria and flow on MHD wave modes: cylindrical geometry. Monthly Notices of the Royal Astronomical Society, 510 (2). pp. 2689-2706. ISSN 0035-8711
Abstract
Magnetohydrodynamic (MHD) waves are routinely observed in the solar atmosphere. These waves are important in the context of solar physics as it is widely believed they can contribute to the energy budget of the solar atmosphere and are a prime candidate to contribute towards coronal heating. Realistic models of these waves are required representing observed configurations such that plasma properties can be determined more accurately, since they cannot be measured directly. This work utilizes a previously developed numerical technique to find permittable eigenvalues under different non-uniform equilibrium conditions in a Cartesian magnetic slab geometry. Here, we investigate the properties of magnetoacoustic waves under non-uniform equilibria in a cylindrical geometry. Previously obtained analytical results are retrieved to emphasize the power and applicability of this numerical technique. Further case studies investigate the effect that a radially non-uniform plasma density and non-uniform plasma flow, modelled as a series of Gaussian profiles, have on the properties of different MHD waves. For all cases the dispersion diagrams are obtained and spatial eigenfunctions calculated which display the effects of the equilibrium inhomogeneity. It is shown that as the equilibrium non-uniformity is increased, the radial spatial eigenfunctions are affected and extra nodes introduced, similar to the previous investigation of a magnetic slab. Furthermore, azimuthal perturbations are increased with increasing inhomogeneity introducing vortical motions inside the waveguide. Finally, 2D and 3D representations of the velocity fields are shown which may be useful for observers for wave mode identification under realistic magnetic waveguides with ever increasing instrument resolution.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | MHD; waves; Sun: oscillations |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Automatic Control and Systems Engineering (Sheffield) 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/M000826/1 INSTITUTE FOR SPACE-EARTH ENVIRONMENTAL RESEARCH UNSPECIFIED EUROPEAN COMMISSION - HORIZON 2020 824135 Science and Technology Facilities Council 2135820 SCIENCE AND TECHNOLOGY FACILITIES COUNCIL ST/V000977/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 02 Mar 2022 17:21 |
Last Modified: | 02 Mar 2022 17:21 |
Status: | Published |
Publisher: | Oxford University Press (OUP) |
Refereed: | Yes |
Identification Number: | 10.1093/mnras/stab3635 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:181922 |