Subject: SOHO/LASCO HALO CME 110307b

UCMEO 93001 10307 2330/
10307 62000 82206 1741/ 173// 333// 42180
10307 61928 82030 45824 11164 1112/
99999

PLAIN

SOHO/LASCO observed a HALO CME on March 07, 2011. This is the second
HALO event on this day.  This event is first seen in C2 at 20:00 UT 
as a bright loop centered at PA 311 degrees.  The front expands 
with a cavity and defined core material.  The event develops to a full
asymmetric HALO event with extensions at all positions. 
The event continues into the C3 field beginning 20:18 to 22:06 UT 
to approximately 26.5 Rsun.

Time/height measurements were marked to only 3 points in C2 with speeds of 2265.2 Km/sec 
at position angle 313 degrees. The event is marked to 6 points in C3 where it 
slightly decelerates.  Speeds average through both fields to 2179.9 Km/sec at 
PA 313 degrees.  Acceleration -25.55 m/sec^s.


SDO/AIA shows a prominence eruption begining at 19:29 UT prior to a flare of 
AR 11164 located at [N24, W58] on disk begining 19:44-20:30 UT with post
arcade the flare produces an AIA wave that is close to global.         
NOAA reports a M3.7 Xray flare of AR 11164 beginning at 19:43-20:58 UT.
STEREO EUVI A 195 shows AR11164 on it's North East quadrant with a flare at 
20:05 UT and a wave following 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/2011/110307b/

Best regards,

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

BT