signature=5dd921e127ca4260f7a83c6b9e1f8542,KINK AND SAUSAGE MODES IN NONUNIFORM MAGNETIC SLABS WITH ...

摘要：

We examine the influence of a continuous density structuring transverse to coronal slabs on the dispersive properties of fundamental standing kink and sausage modes supported therein. We derive generic dispersion relations (DRs) governing linear fast waves in pressureless straight slabs with general transverse density distributions, and focus oncases where the density inhomogeneity takes place in a layer of arbitrary width and in arbitrary form. The physical relevance of the solutions to the DRs is demonstrated by the corresponding time-dependent computations. For all profiles examined, the lowestorder kink modes are trapped regardless of longitudinal wavenumber , and their periods and damping times are heavily influenced by how the transverse density profile is prescribed, in particularthe length scale. These modes have sufficiently high quality to be observable only for physical parameters representative of flare loops. We conclude that while the simpler DR pertinent to a step function profile can be used for the lowestorder kink modes, the detailed information on the transverse density structuring needs to be incorporated into studies of sausage modes and higherorder kink modes.

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