Ruderman, M.S. orcid.org/0000-0003-2324-8466 and Petrukhin, N.S. (2022) Existence of purely Alvén waves in magnetic flux tubes with arbitrary cross-sections. Physics, 4 (3). pp. 865-872.
Abstract
We study linear torsional Alfvén waves in a magnetic flux tube with an arbitrary cross-section. We assume that the equilibrium magnetic field is propagating in the z-direction in Cartesian coordinates x,y, and z. The tube cross-section is bounded by a smooth closed curve. Both plasma and magnetic field are homogeneous outside this curve. The magnetic field magnitude is a function of x and y, while the density is a product of two functions: one dependent on z and the other dependent on x and y. As a result, the Alfvén speed is also equal to V0(x,y) times a function of z. We define Alfvén waves as waves that do not disturb plasma density. We show that these waves can exist only when the magnetic field magnitude is a function of V0. When the condition of existence of Alfvén waves is satisfied, the waves are polarised in the directions tangent to the level lines of V0(x,y) and orthogonal to the equilibrium magnetic field. We found that the Alfvén wave amplitude has a specific form that depends on a particular coordinate system.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 The Authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
Keywords: | plasma; magnetohydrodynamics; Alfvén waves; solar atmosphere |
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: | 08 Aug 2022 10:44 |
Last Modified: | 08 Aug 2022 10:44 |
Status: | Published |
Publisher: | MDPI AG |
Refereed: | Yes |
Identification Number: | 10.3390/physics4030055 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:189779 |