A huge slowly decaying arcade preceding a vast CME

Science nugget Dec 15, 1997

(Click on a pictures to see a larger, more visible, versions.)

This huge arcade development is one of the brightest and largest we have seen recently. The GOES record on the right (a whole week!) shows an LDE with an extremely slow initial decay, no doubt related to the size of the arcade. The Yohkoh tohbans at KSC estimated a scale of 0.6 solar radii. Authoritative rumor has it that a vast CME was comprehensively observed by LASCO, and why not. A comparative analysis of SXT and LASCO motions would be extremely interesting and might offer us a chance to observe the 3-D nature of the development. Sorry not to have links to the LASCO movies here, but try SOHO directly if you please.

We have also made a movie of this fine event. Unfortunately the Web view of this really does not do justice to the delicate tracery of filamentary structures as this thing unwinds and erupts. This is reminiscent of the Oct. 5, 1996 event (Watari et al., Oslo proceedings), except that in this case we are seeing it on the disk rather than far beyond the limb. Note that the later brightening is in a different arcade, also related to AR8113.

HSH 12-Dec-97 (email hudson@isass0.solar.isas.ac.jp)