Abstract

We present magnetohydrodynamic (MHD) simulations of the evolution from quasi-equilibrium to eruption of a prominence-forming twisted coronal flux rope under a coronal streamer. We have compared the cases with and without the formation of prominence condensations, as well as the case where promine... Show moreWe present magnetohydrodynamic (MHD) simulations of the evolution from quasi-equilibrium to eruption of a prominence-forming twisted coronal flux rope under a coronal streamer. We have compared the cases with and without the formation of prominence condensations, as well as the case where prominence condensations form but we artificially initiate the draining of the prominence. We find that the prominence weight has a significant effect on the stability of the flux rope and can significantly increase the loss-of-equilibrium height. The flux rope can be made to erupt earlier by initiating draining of the prominence mass. We have also performed a simulation where large-amplitude longitudinal oscillations of the prominence are excited during the quasi-static phase. We find that the gravity force along the magnetic field lines is the major restoring force for the oscillations, in accordance with the "pendulum model," although the oscillation periods are higher (by about 10%-40%) than estimated from the model because of the dynamic deformation of the field line dips during the oscillations. The oscillation period is also found to be slightly smaller for the lower part of the prominence in the deeper dips compared to the upper part in the shallower dips. The oscillations are quickly damped out after about two to three periods and are followed by prominence draining and the eventual eruption of the prominence. However, we do not find a significant enhancement of the prominence draining and earlier onset of eruption with the excitation of the prominence oscillations compared to the case without. Show less