Subject: SOHO/LASCO Partial HALO CME 110511

UCMEO 93001 10511 1930/
10511 60248 80830 2181/ 067// 323// 40387
10511 60217 80253 45322 ///// 2112/
99999

PLAIN

SOHO/LASCO observed a Partial HALO CME on May 11, 2011.  Event is first seen in        
C2 at 02:48 UT as a bright loop centered at PA 293 degrees followed by a cavity
and bright core material.  The front expands with extensions PA 218-67 degrees
for a total coverage of 209 degrees over the Northern hemisphere. The event continues
into the C3 field beginning 03:30 to 08:30 UT out to approximately 14.2 Rsun.

Time/height measurements were marked to 7 points in C2 with speeds of 506.6 Km/sec
at position angle 297 degrees. The event is marked to 16 points in C3 where it
slightly decelerates.  Speeds average through both fields to 378.6 Km/sec at 
PA 294 degrees. 

SDO/AIA shows elevating filament material centered at [N22,W53] then erupting
in a duel ribbon fashion beginning 02:17-02:53 UT between AR 11207 and AR 11205.
The eruption produces a dimming over the Northwest and wave.         
STEREO COR2 A sees a burst beginning 03:24 UT in the NE field.
EUVI 195 A shows an eruption 02:35-02:55 UT with dimming and wave in the NE.
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/2011/110511/

Best regards,

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

BT