Bibcode
Díaz, A. J.; Oliver, R.; Ballester, J. L.
Bibliographical reference
In: Solar variability: from core to outer frontiers. The 10th European Solar Physics Meeting, 9 - 14 September 2002, Prague, Czech Republic. Ed. A. Wilson. ESA SP-506, Vol. 2. Noordwijk: ESA Publications Division, ISBN 92-9092-816-6, 2002, p. 593 - 596
Advertised on:
12
2002
Citations
0
Refereed citations
0
Description
Some observations suggest that quiescent solar prominences can be
considered as composed by small-scale loops, or fibrils, which are
stacked one after another in both the vertical and horizontal
directions. In a previous work we studied, in Cartensian geometry, the
propagation of fast MHD waves in a two-dimensional magnetostatic model
representing one of these fibrils. In this paper we use a more realistic
model based on a cylindrically symmetric flux tube and study the
propagation of fast MHD waves in this structure. Among other
conclusions, our results show that all sausage modes (m=0) possess a
cutoff frequency, while the fundamental kink and fluting modes (m>0)
do not show such a cut-off. Moreover, the spatial structure of the modes
below the cut-off frequency is such that in this geometry perturbations
are confined in the dense part of the fibril, the leakage of energy
towards the coronal medium being very small, which may prevent the
excitation of neighbouring fibrils. Finally, diagnostic diagrams
displaying the oscillatory period in terms of some equilibrium
parameters are provided in order to allow for a comparison between our
theoretical results and those coming from observations.