Compressibility effects on the gravitational instability of a plasma-vacuum interface

The stability of gravitational compressible surface modes of a plasma-vacuum interface is investigated. Stratified equilibrium profiles of density and magnetic field in the plasma are considered. The corresponding boundary conditions for magnetohydrodynamic linear perturbations are deduced. Three ty...

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Autores principales: González, Alejandro Guillermo, Gratton, Julio
Publicado: 1990
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07413335_v32_n1_p3_Gonzalez
http://hdl.handle.net/20.500.12110/paper_07413335_v32_n1_p3_Gonzalez
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_07413335_v32_n1_p3_Gonzalez
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spelling paper:paper_07413335_v32_n1_p3_Gonzalez2023-06-08T15:44:37Z Compressibility effects on the gravitational instability of a plasma-vacuum interface González, Alejandro Guillermo Gratton, Julio The stability of gravitational compressible surface modes of a plasma-vacuum interface is investigated. Stratified equilibrium profiles of density and magnetic field in the plasma are considered. The corresponding boundary conditions for magnetohydrodynamic linear perturbations are deduced. Three types of surface normal modes (slow, intermediate and fast) may appear. The slow mode is unstable below a critical wavenumber. The stability criterion is affected in general by the compressibility. The growth rate of the unstable modes is increased by compressibility. It is shown that for 'flute' or pure interchange modes with respect to the vacuum magnetic field (but not with respect to the equilibrium magnetic field in the plasma) the compressibility enlarges the instability domain of surface modes. The interval of existence of unstable surface perturbations, as well as their growth rates, are larger than those of the internal unstable modes. Intervals of non-existence of surface modes appear for the flute perturbations with respect to the plasma magnetic field. The critical values of the wavenumber below which the modes are unstable, are discussed in general. Fil:Gonzalez, A.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Gratton, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 1990 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07413335_v32_n1_p3_Gonzalez http://hdl.handle.net/20.500.12110/paper_07413335_v32_n1_p3_Gonzalez
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description The stability of gravitational compressible surface modes of a plasma-vacuum interface is investigated. Stratified equilibrium profiles of density and magnetic field in the plasma are considered. The corresponding boundary conditions for magnetohydrodynamic linear perturbations are deduced. Three types of surface normal modes (slow, intermediate and fast) may appear. The slow mode is unstable below a critical wavenumber. The stability criterion is affected in general by the compressibility. The growth rate of the unstable modes is increased by compressibility. It is shown that for 'flute' or pure interchange modes with respect to the vacuum magnetic field (but not with respect to the equilibrium magnetic field in the plasma) the compressibility enlarges the instability domain of surface modes. The interval of existence of unstable surface perturbations, as well as their growth rates, are larger than those of the internal unstable modes. Intervals of non-existence of surface modes appear for the flute perturbations with respect to the plasma magnetic field. The critical values of the wavenumber below which the modes are unstable, are discussed in general.
author González, Alejandro Guillermo
Gratton, Julio
spellingShingle González, Alejandro Guillermo
Gratton, Julio
Compressibility effects on the gravitational instability of a plasma-vacuum interface
author_facet González, Alejandro Guillermo
Gratton, Julio
author_sort González, Alejandro Guillermo
title Compressibility effects on the gravitational instability of a plasma-vacuum interface
title_short Compressibility effects on the gravitational instability of a plasma-vacuum interface
title_full Compressibility effects on the gravitational instability of a plasma-vacuum interface
title_fullStr Compressibility effects on the gravitational instability of a plasma-vacuum interface
title_full_unstemmed Compressibility effects on the gravitational instability of a plasma-vacuum interface
title_sort compressibility effects on the gravitational instability of a plasma-vacuum interface
publishDate 1990
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07413335_v32_n1_p3_Gonzalez
http://hdl.handle.net/20.500.12110/paper_07413335_v32_n1_p3_Gonzalez
work_keys_str_mv AT gonzalezalejandroguillermo compressibilityeffectsonthegravitationalinstabilityofaplasmavacuuminterface
AT grattonjulio compressibilityeffectsonthegravitationalinstabilityofaplasmavacuuminterface
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