EDP Sciences
Free access
Issue
A&A
Volume 379, Number 3, December I 2001
Page(s) 1083 - 1097
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20011351
A&A 379, 1083-1097 (2001)
DOI: 10.1051/0004-6361:20011351

Fast MHD oscillations in prominence fine structures

A. J. Díaz1, R. Oliver1, R. Erdélyi2 and J. L. Ballester1

1  Departament de Física, Universitat de les Illes Balears, 07071 Palma de Mallorca, Spain
    e-mail: ramon.oliver@uib.es; dfsjlb0@uib.es
2  Space & Atmosphere Research Center, Department of Applied Mathematics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, England, UK
    e-mail: Robertus@sheffield.ac.uk

(Received 21 May 2001 / Accepted 20 September 2001 )

Abstract
High-resolution observations suggest that quiescent solar prominences are made of small-scale fibrils stacked one after another in both the vertical and horizontal directions. These fibrils are interpreted as the cool, highermost part of much larger coronal loops which are rooted in the solar photosphere. On the other hand, there is some evidence showing that small amplitude oscillations in prominences can affect individual or groups of fibrils, which vibrate with their own periods. Using a simple magnetostatic model to represent the fibril structure of quiescent solar prominences, Joarder et al. (1997) investigated some oscillatory properties of the Alfvén and fast magnetohydrodynamic modes. In this paper, with a proper treatment of boundary conditions, we reexamine their configuration and explore more deeply the basic features (mainly frequency and spatial structure) of the fast mode. The main conclusion is that, for reasonable values of the fibril's width, perturbations extend far away from its axis and, therefore, a single oscillating fibril can excite oscillations in neighbouring ones.


Key words: Sun: oscillations -- Sun: magnetic fields -- Sun: corona -- Sun: prominences

Offprint request: A. J. Díaz, toni@hubble.uib.es





© ESO 2001