Subject: SOHO/LASCO Partial HALO CME 110910a

UCMEO 93001 10912 1713/
10910 60312 81154 2361/ 077// 323// 40782
10909 62257 80518 42833 ///// 2212/
99999

PLAIN

SOHO/LASCO observed a Partial HALO CME on September 10, 2011.  Event is first
seen in C2 at 03:12 UT as wide bright loop centered at PA 329 degrees followed
by multiple cores. The front expands with extensions PA 236-77 degrees for a
total coverage of 201 degrees over the North East. The event continues into the
C3 field beginning 04:06 to 11:54 UT out to the edge of view at 30 Rsun.

Time/height measurements were marked at 9 points in C2 with speeds of 699.2 Km/sec
at position angle 327 degrees. The event is marked to 13 points in C3 where it
accelerates.  Speeds average through both fields to 782.0 Km/sec at PA 325 degrees.
Acceleration of 16.25 m/sec^s.

SDO/AIA 193 shows activated filament material beginning 16:33 UT.  Eruption begins
approximately 22:57 - 05:018 UT on disk with dimming along north/south filament 
channel center located [N33, W28] along with post arcading.  A flare is triggered
from AR 11283 at 07:24 UT from the adjacent filament to it's east.     
STEREO EUVI A beacon data shows a lift-off 00:25-05:05 UT on NE limb.  A data
gap of 22:25-00:25 misses the beginning of the event.
COR2 B beginning 03:35 UT, a large loop over it's NW limb.
Preliminary time/height measure at 9 pts gives speeds 632.2 km/sec.
COR2 A beginning 03:24 UT, large loop over the NE.
Preliminary time/height measure at 9 pts gives speeds 646.0 km/sec.

This is most probably the cause of the Partial HALO event seen in LASCO.

   
The observation of this event is considered 'GOOD'. This CME is determined a FRONTSIDED event.

Images and movies and time/height information for this event is available on the web at:

http://umbra.nascom.nasa.gov/lasco/observations/halo/2011/110910a/

Best regards,

Kevin Schenk
Solar Heliospheric Observatory
EIT and LASCO Operations
NASA-Goddard Space Flight Center, USA

BT