Causes of Prominence Eruptions

Several mechanisms that have been used to explain the eruption of prominences are discussed. In various magnetic configurations used to model the initial equilibrium of prominences, different parameters must be achieved for an eruption to begin. In sheared arcade models, there should be a significant increase in shear. In flux-rope models, there is a critical value of twist at which kink instability occurs. The catastrophic loss of equilibrium and torus instability, which are very popular explanations for eruptive events, require a rather steep decrease in the coronal magnetic field with height. This characteristic of the field is described by the decay index, which has critical values dependent on some properties of the model. The results of critical decay-index estimations in observed eruptive events are presented.