Halo CME Mail Date: Mon, 5 Nov 2001 14:22 From: Gareth Lawrence Subject: Full Halo CME on 2001/11/04 ------------------------------------------------------------------------ UCMEO 93001 11105 1900/ 11104 61635 92003 0001/ 360// 233// 51620 11104 61603 81657 41806 09684 1//1/ 99999 PLAIN BT LASCO observed a full halo CME on 2001/11/04. The event was first observed in C2 at 16:35 UT as a very fast, bright loop front over the W limb; by 16:50 UT the C2 occulting disk was surrounded. The front first appeared in C3 at 16:45 UT with full coverage of the C3 occultor by 17:00 UT. The plane of sky speed of the front was measured as 1620 km/s at PA 251 (SW) with discernible acceleration through both coronagraphs' fields of view. The CME was most probably associated with an X1.0 X-ray flare in AR9684 between 16:03 and 16:57 UT with peak emission at 16:20 UT. SEC places the flare at S17W20. EIT was in bakeout mode at the time and therefore no EUV observations are available from SOHO. Please note that the third line of the UCMEO code above has been completed using GOES X-ray data from SEC's web pages. Note also that a proton storm was also observed in association with this event and that the later C3 images are particularly degraded. Images and movies of this event are available at: ftp://ares.nrl.navy.mil/pub/lasco/halo/20011104 In addition to this large event, LASCO observed another full halo CME and a wide partial halo CME. Reports for both of these CMEs are being prepared, but since they were both substantially slower and both occured no more than fifteen hours before this main event, it seem likely that a single complex ejecta will be encountered at 1 AU rather than several distinct events. Best wishes, Gareth Lawrence. ++ | Gareth Lawrence, E-mail:grl@kreutz.nascom.nasa.gov | | SOHO-LASCO Operations Scientist, | | CUA, Mail Code 682.3, | | NASA Goddard Space Flight Center, Phone: +1-301-286-2941 | | Building 26, Room G-1, +1-301-286-3447 | | Greenbelt, MD 20771. Fax: +1-301-286-0264 | ++