Bibcode
Díaz, A. J.; Zaqarashvili, T.; Roberts, B.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 455, Issue 2, August IV 2006, pp.709-717
Fecha de publicación:
8
2006
Revista
Número de citas
45
Número de citas referidas
44
Descripción
Aims.We discuss a simple model of a line-tied coronal arcade with
piecewise constant density to explore the effects of curvature on
radially polarised fast modes.Methods.A partial differential
equation is derived for the velocity perturbation of the fast modes and
it is solved analytically in terms of Bessel functions of half integer
order, obtaining a dispersion relation.Results.The properties of
the modes are studied in terms of the parameters. All the modes are
leaky under these conditions. Besides the usual kink and sausage modes,
new families are described: the vertical, swaying (longitudinal), and
rocking modes arise.Conclusions.The damping rates are similar to
observed rates. For thin arcades the modes are markedly different from
those of a straight slab and resemble more the modes of a circular
membrane.