Longitudinal oscillations in density stratified and expanding solar waveguides

Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study th...

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Guardado en:
Detalles Bibliográficos
Publicado: 2012
Materias:
magnetohydrodynamics (MHD)
Sun: chromosphere
Sun: corona
Sun: oscillations
waves
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v748_n2_p_LunaCardozo
http://hdl.handle.net/20.500.12110/paper_0004637X_v748_n2_p_LunaCardozo
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_0004637X_v748_n2_p_LunaCardozo
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spelling paper:paper_0004637X_v748_n2_p_LunaCardozo2023-06-08T14:29:04Z Longitudinal oscillations in density stratified and expanding solar waveguides magnetohydrodynamics (MHD) Sun: chromosphere Sun: corona Sun: oscillations waves Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study the eigenmodes of these oscillations. It is our specific aim to understand what happens to these MHD waves generated in flux tubes with non-constant (e.g., expanding or magnetic bottle) cross-sectional area and density variations. The governing equation of the longitudinal mode is derived and solved analytically and numerically. In particular, the limit of the thin flux tube approximation is examined. The general solution describing the slow longitudinal MHD waves in an expanding magnetic flux tube with constant density is found. Longitudinal MHD waves in density stratified loops with constant magnetic field are also analyzed. From analytical solutions, the frequency ratio of the first overtone and fundamental mode is investigated in stratified waveguides. For small expansion, a linear dependence between the frequency ratio and the expansion factor is found. From numerical calculations it was found that the frequency ratio strongly depends on the density profile chosen and, in general, the numerical results are in agreement with the analytical results. The relevance of these results for solar magneto-seismology is discussed. © 2012. The American Astronomical Society. All rights reserved. 2012 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v748_n2_p_LunaCardozo http://hdl.handle.net/20.500.12110/paper_0004637X_v748_n2_p_LunaCardozo
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic magnetohydrodynamics (MHD)
Sun: chromosphere
Sun: corona
Sun: oscillations
waves
spellingShingle magnetohydrodynamics (MHD)
Sun: chromosphere
Sun: corona
Sun: oscillations
waves
Longitudinal oscillations in density stratified and expanding solar waveguides
topic_facet magnetohydrodynamics (MHD)
Sun: chromosphere
Sun: corona
Sun: oscillations
waves
description Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study the eigenmodes of these oscillations. It is our specific aim to understand what happens to these MHD waves generated in flux tubes with non-constant (e.g., expanding or magnetic bottle) cross-sectional area and density variations. The governing equation of the longitudinal mode is derived and solved analytically and numerically. In particular, the limit of the thin flux tube approximation is examined. The general solution describing the slow longitudinal MHD waves in an expanding magnetic flux tube with constant density is found. Longitudinal MHD waves in density stratified loops with constant magnetic field are also analyzed. From analytical solutions, the frequency ratio of the first overtone and fundamental mode is investigated in stratified waveguides. For small expansion, a linear dependence between the frequency ratio and the expansion factor is found. From numerical calculations it was found that the frequency ratio strongly depends on the density profile chosen and, in general, the numerical results are in agreement with the analytical results. The relevance of these results for solar magneto-seismology is discussed. © 2012. The American Astronomical Society. All rights reserved.
title Longitudinal oscillations in density stratified and expanding solar waveguides
title_short Longitudinal oscillations in density stratified and expanding solar waveguides
title_full Longitudinal oscillations in density stratified and expanding solar waveguides
title_fullStr Longitudinal oscillations in density stratified and expanding solar waveguides
title_full_unstemmed Longitudinal oscillations in density stratified and expanding solar waveguides
title_sort longitudinal oscillations in density stratified and expanding solar waveguides
publishDate 2012
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v748_n2_p_LunaCardozo
http://hdl.handle.net/20.500.12110/paper_0004637X_v748_n2_p_LunaCardozo
_version_ 1768542718777098240

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