Oscillations of a quiescent solar prominence embedded in a hot corona

The magneto-acoustic-gravity modes of vibration of a Kippenhahn-Schlueter prominence model, surrounded by an external medium representing the solar corona, are investigated. Modes which do not disappear when the coronal region is removed are called internal modes, while modes which do not disappear when the prominence is removed are called external modes. Three modes were found which could be labeled as either internal or external modes, since they do not disappear when either region is removed. The results of this study suggest that short-period oscillations in limb prominences may be caused by the fundamental and first harmonics of the internal magneto-acoustic-gravity slow and Alfven modes, while the reported long-period oscillations in limb prominences may be the result of the hybrid slow mode. Short-period oscillations lasting a few minutes and detected in filaments may be related to internal fast modes, while the hybrid fast mode causes vertical oscillations with periods of approximately 20 min.