Large-Scale Activity Initiated BY Halo CMEs

We summarize results of our recent studies of CME-associated EUV dimmings and coronal waves by `derotated' fixed-difference SOHO/EIT heliograms at 195 Å with 12-min intervals and at 171, 195, 284, 304 Å with 6-h intervals. Correctness of the derotated fixed-difference technique is confirmed by the consideration of the Bastille Day 2000 event. We also demonstrate that long narrow channeled dimmings and anisotropic coronal waves are typical of the complex global solar magnetosphere near the solar cycle maximum. Homology of large-scale dimmings and coronal waves takes place in a series of recurrent eruptive events. Along with dimmings coinciding entirely or partially in all four EIT bands, there exist dimmings that appear different, mainly in the transition-region line of 304 Å and high-temperature coronal line of 284 Å.