The structure of fast sausage waves in current-carrying coronal loops
We study fast sausage waves in a model coronal loop that consists of a cylindrical core with axial magnetic field and coaxial annulus with purely azimuthal magnetic field. The magnetic field is discontinuous at the tube and core boundaries, and there are surface currents with the opposite directi...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-09-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/32/1189/2014/angeo-32-1189-2014.pdf |
| Summary: | We study fast sausage waves in a model coronal loop that consists of a
cylindrical core with axial magnetic field and coaxial annulus with purely
azimuthal magnetic field. The magnetic field is discontinuous at the tube and
core boundaries, and there are surface currents with the opposite directions
on these boundaries. The principal mode of fast sausage waves in which the
magnetic pressure perturbation has no nodes in the radial direction can exist
for arbitrary wavelength. The results for the fundamental radial mode of
sausage waves are applied to the interpretation of observed periodic
pulsations of microwave emission in flaring loops with periods of a few tens
of seconds. Radial plasma motion has opposite directions at the tube and core
boundaries. This leads to the periodic contraction and expansion of the
annulus. We assume that the principal mode of fast sausage waves in the
current-carrying coronal loops is able to produce a current sheet. However,
the nonlinear analysis is needed to confirm this conjecture. |
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| ISSN: | 0992-7689 1432-0576 |