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| Titel |
Dynamics of nonlinear resonant slow MHD waves in twisted flux tubes |
| VerfasserIn |
R. Erdélyi, I. Ballai |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 9, no. 2 ; Nr. 9, no. 2, S.79-86 |
| Datensatznummer |
250006689
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| Publikation (Nr.) |
 copernicus.org/npg-9-79-2002.pdf |
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| Zusammenfassung |
| Nonlinear resonant
magnetohydrodynamic (MHD) waves are studied in weakly dissipative
isotropic plasmas in cylindrical geometry. This geometry is suitable and
is needed when one intends to study resonant MHD waves in magnetic flux
tubes (e.g. for sunspots, coronal loops, solar plumes, solar wind, the
magnetosphere, etc.) The resonant behaviour of slow MHD waves is confined
in a narrow dissipative layer. Using the method of simplified matched
asymptotic expansions inside and outside of the narrow dissipative layer,
we generalise the so-called connection formulae obtained in linear MHD for
the Eulerian perturbation of the total pressure and for the normal
component of the velocity. These connection formulae for resonant MHD
waves across the dissipative layer play a similar role as the well-known
Rankine-Hugoniot relations connecting solutions at both sides of MHD shock
waves. The key results are the nonlinear connection formulae found in
dissipative cylindrical MHD which are an important extension of their
counterparts obtained in linear ideal MHD (Sakurai et al., 1991), linear
dissipative MHD (Goossens et al., 1995; Erdélyi, 1997) and in nonlinear
dissipative MHD derived in slab geometry (Ruderman et al., 1997). These
generalised connection formulae enable us to connect solutions obtained at
both sides of the dissipative layer without solving the MHD equations in
the dissipative layer possibly saving a considerable amount of CPU-time
when solving the full nonlinear resonant MHD problem. |
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