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Fast magnetoacoustic waves in curved coronal loops. I, Trapped and leaky modes

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Verwichte, E. (Erwin), Foullon, C. (Claire) and Nakariakov, V. M. (Valery M.). (2006) Fast magnetoacoustic waves in curved coronal loops. I, Trapped and leaky modes. Astronomy & Astrophysics, Vol.446 (No.3). pp. 1139-1149. ISSN 0004-6361

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Official URL: http://dx.doi.org/10.1051/0004-6361:20053955

Abstract

A study of vertically polarised fast magnetoacoustic waves in a curved coronal loop is presented. The loop is modeled as a semi-circular magnetic slab in the zero plasma-β limit. The governing equations for linear waves are derived. We show that the wave mode behaviour depends on the slope of the equilibrium density profile, which is modeled as a piece-wise continuous power law curve of index α. For all profiles, except for α = −4, wave modes are not trapped in the loop and leak out into the external medium through wave tunneling. The particular case of α = −4, which corresponds to a linearly increasing Alfvén speed profile, is examined in more detail as this is the only model that can support trapped wave modes. We compare the results with a straight slab model and find similar behaviour. Coupling between sausage and kink wave modes has not been found in the model.

Item Type:

Journal Article

Subjects:

Q Science > QB Astronomy

Divisions:

Faculty of Science > Physics

Library of Congress Subject Headings (LCSH):

Magnetohydrodynamics, Sun -- Loop prominences, Sun -- Corona, Solar oscillations

Journal or Publication Title:

Astronomy & Astrophysics

Publisher:

EDP Sciences

ISSN:

0004-6361

Official Date:

February 2006

Dates:

Date	Event
February 2006	Published

Volume:

Vol.446

Number:

No.3

Page Range:

pp. 1139-1149

Identification Number:

10.1051/0004-6361:20053955

Status:

Peer Reviewed

Access rights to Published version:

Open Access

Funder:

Royal Society (Great Britain), Leverhulme Trust (LT), Particle Physics and Astronomy Research Council (Great Britain) (PPARC)

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