Halo CME MailHalo CME Mail Date: Wed, 27 Aug 2003 16:53 From: Gareth Lawrence Subject: Partial Halo CME on 2003/08/25, probably frontsided UCMEO 93001 30827 2115/ 30825 60127 92142 1001/ 140// 223// 40308 30825 60212 80300 24111 10442 1112/ 99999 PLAIN BT LASCO/EIT observed a wide partial halo CME on 2003/08/25. The event was first observed in C2 data at 01:27 UT as a system of faint loop fronts rising along a streamer in the SW; this front spanned 140 deg from PA 100 - PA 240 by 03:06 UT. The front first appeared in C3 at 09:18 UT with maximal coverage of the C3 occultor by 19:00 UT. The mean plane-of-sky speed for this event was 308 km/s at PA 185, with moderate acceleration. EIT observed an C3.6 X-ray flare between 02:12 - 03:00 UT with peak emission at 02:36 UT. The source of the flare was AR 0442 centered on S11E41. A separate CME probably associated with this flare can be seen in LASCO images along the streamer in the SE from 03:26 UT; afterwards the slow fronts in the SW appear to span over the S pole and to the vicinity of this streamer. Note that the faint fronts had been visible in the SW for a considerable time prior to the flare in the SE. A modest EIT wave and dimming were observed in association with this event, primarily to the W of the AR. This event has therefore been determined probably frontsided. Movies and images of this event will shortly available at: ftp://ares.nrl.navy.mil/pub/lasco/halo/20030825 Best wishes, Gareth Lawrence. +----------PLEASE NOTE NEW EMAIL ADDRESS-----------+ Gareth Lawrence, grl@grace.nascom.nasa.gov SOHO-LASCO Operations Scientist, CUA, MC 682.3, Bldg 26, Rm 001, F: +1-301-286-0264 NASA Goddard Space Flight Center, Greenbelt, MD 20771. P: +1-301-286-2941 ++