We consider theoretically the possible modes of oscillation of a solar quiescent prominence, treating the prominence as a plasma slab embedded in a uniform, line-tied magnetic field that is inclined at a small angle (≍2O°) to the long axis of the slab. Particularly interesting is the appearance of a string Alfvén mode that is analogous to the fundamental mode of vibration of a stretched string loaded with a heavy mass at its centre. This mode, along with a slow internal mode of the slab, may correspond to the observed long period (40-90 min) oscillation of quiescent prominences. Intermediate periodicities, in the range 8-20 min, may be associated with an internal Alfvén mode and a fast string mode. Short periodicities, in the range 2-5 min, may be due to an internal fast mode in the prominence slab.
Astronomy and Astrophysics
- Pub Date:
- September 1993
- magnetohydrodynamics - Sun: magnetic fields - Sun: prominences