SPEEDS OF RISING POST-FLARE STRUCTURES

There are basically two kinds of post-hare coronal structures: those r ising with decreasing speed, and others which rise with constant speed for a long period of time. As a rule, those structures with decreasin g speed are post-flare loop systems, while those rising with constant speed are post-flare giant arches. However, there are exceptions. We d emonstrate several cases of post-flare loop systems which rise with co nstant speed for many hours, three of them observed by Yohkoh. These o bservations imply that the Kopp and Pneuman interpretation of post-har e loops as sequentially reconnecting open field lines cannot be genera lly valid. The most likely interpretation is that all post-flare loop systems start with the Kopp and Pneuman process, but in some of them l ater-formed loops begin to be continuously heated; thus they cease to cool and begin to expand into the corona. This kind of post-hare loops might represent an intermediate stage between the ordinary post-flare loops and post-flare giant arches.