Subject: SOHO/LASCO Partial HALO CME 110307

UCMEO 93001 10307 2130/
10307 61448 82042 2431/ 117// 333// 40634
10307 61348 81415 12111 11166 1112/
99999

PLAIN

SOHO/LASCO observed a Partial HALO CME on March 07, 2011.  Event is first seen in        
C2 at 14:48 UT as a bright loop centered at PA 40 degrees followed by a deep
cavity.  The impulsive front expands with extensions PA 243-117 degrees for a total
coverage of 234 degrees over the Northern hemisphere. The event continues into the 
C3 field beginning 15:06 to 20:42 UT out to approximately 24 Rsun.

Time/height measurements were marked to 5 points in C2 with speeds of 793.8 Km/sec 
at position angle 45 degrees. The event is marked to 16 points in C3 where it 
slightly decelerates.  Speeds average through both fields to 634.0 Km/sec at 
PA 44 degrees.  Acceleration -17.41 m/sec^s.


SDO/AIA shows a flare of AR 11166 located at [N11, E21] on disk 
begining 13:48-14:15 UT with a dimming over the North, NE projection
and a small wave.         
NOAA reports a long duration M1.9 Xray flare of AR 11166 beginning at 13:45-14:56 UT.
STEREO COR2 B sees the impulsive burst beginning 14:54 UT in it's NW limb as
does EUVI 195 shows AR11166 on it's west limb with a flare at 13:55 UT in the 
beacon data. 
This is most probably the cause of the 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/110307/

Best regards,

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

BT