On the Transition Region Explosive Events

Open Access
Publisher Website
Google Scholar
Abstract
We describe the properties of high-velocity and explosive events in the solar transition region determined from time series of data taken by the Transition Region and Coronal Explorer and the SUMER instrument on the Solar and Heliospheric Observatory (SOHO) simultaneously in several chromospheric and transition region lines co-aligned with high-resolution Michelson Doppler Imager (SOHO) magnetograms. We outline what the various features of these events can tell us about the heating mechanisms and formation of plasma flows. Our results strongly support the mechanism of hydrodynamic cumulation of energy associated with the cascade of shock waves produced by colliding and reconnecting flux tubes in the photospheric network (as recently discussed by T. D. Tarbell et al.). We find that the majority of the explosive events are caused by the explosive instability occurring in the presence of the behind-shock downflows, and less than 10% can be explained by the direct collision of shock fronts.