Halo CME Mail

Date: Tue, 18 Nov 2003 16:12

From: Gareth Lawrence

Subject: 'Full' Halo CME on 2003/11/18, frontsided

Status: O

UCMEO 93001 31118 2000/
31118 60806 91242 0001/ 360// 223// 41175
31118 60736 90900 11803 10501 1112/

LASCO and EIT observed a 'full' halo CME on 2003/11/18. A wide 
faint loop front was seen in C2 at 08:06 UT filling the SE 
quadrant but brightest in the S; at 08:26 UT this front had 
faint extensions up to the N pole. At 08:50 UT a second, much
brighter, front appeared spanning ~160 deg from the SE to NW
and with fainter extensions to the N pole. Thus between the
two sets of fronts there was full coverage of the C2 occultor 
by 08:50 UT, albeit rather faint in the NE. The bright front
first appeared in C3 images in the S at 08:42 UT and had
developed to a full halo CME by 09:18 UT. The mean plane-of-sky 
speed was 1175 km/s, measured at PA 177 with possible evidence 
for slight acceleration.

The CME was probably associated with complex activity in and 
around AR 0501 between 07:36 - 09:00 UT. EIT observed two 
flares between 07:36 - 08:00 UT and 08:12 - 09:00 UT. The first 
flare was centered at N03E18 and the second a little to the S 
and W. Additionally, a filament channel to the S and W of the
active region was activated following the first flare and
subsequently erupted. SEC records two flares, classed as M3.2
and M3.9, between 07:16 - 08:06 UT and 08:12 - 08:59 UT 
respectively, from AR 0498 located N00E18. Both an EIT wave and 
dimming were observed in association with this event. This event 
has therefore been determined frontsided.

Images and movies will shortly be made available at  


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