Tracking Large-Scale Propagating Coronal Wave Fronts (EIT Waves) using Automated Methods

Abstract

Recently developed mapping algorithms allow automated tracking of a propagating coronal wave, enabling the finding of reproducible fronts and propagation trajectories. Coronal observations taken by the Transition Region and Coronal Explorer (TRACE) on 1998 June 13 show a large-scale bright wave front, comparable to ``EIT waves'' seen with the Extreme Ultraviolet Imaging Telescope aboard the Solar and Heliospheric Observatory ( SOHO EIT). Cross sections measuring density perturbations show roughly Gaussian wave structure, suggesting a single propagating compression front. The wave fronts are also found to propagate nonuniformly, unlike the circular fronts often seen with SOHO EIT. Any perceived dissimilarity between EIT waves and the bright propagating fronts seen by TRACE, however, can be explained by differences in the typical observing sequences of the two instruments.