Bibcode
DOI
Arregui, Iñigo; Terradas, Jaume; Oliver, Ramón; Luis Ballester, José
Bibliographical reference
The Astrophysical Journal, Volume 674, Issue 2, pp. 1179-1190.
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2
2008
Journal
Citations
13
Refereed citations
13
Description
Observations of transverse coronal loop oscillations very often show the
excitation and damping of oscillations in groups of coronal loops rather
than in individual and isolated structures. We present results on the
oscillatory properties (periods, damping rates, and spatial distribution
of perturbations) for resonantly damped oscillations in a system of two
inhomogeneous coronal slabs and compare them to the properties found in
single-slab loop models. A system of two identical coronal loops is
modeled, in Cartesian geometry, as being composed of two density
enhancements. The linear magnetohydrodynamic (MHD) wave equations for
oblique propagation of waves are solved, and the damping of the
different solutions, due to the transverse inhomogeneity of the density
profile, is computed. The physics of the obtained results is analyzed by
an examination of the perturbed physical variables. We find that, due to
the interaction between the loops, the normal modes of oscillation
present in a single slab split into symmetric and antisymmetric
oscillations when a system of two identical slabs is considered. The
frequencies of these solutions may differ from the single slab results
when the distance between the loops is of the order of a few slab
widths. Oblique propagation of waves weakens this interaction, since
solutions become more confined to the edges of the slabs. The damping is
strong for surface-like oscillations, while sausage body-like solutions
are unaffected. For some solutions, and small slab separations, the
damping in a system of two loops differs substantially from the damping
of a single loop.