SOHO/LASCO Partial HALO CME 120118

UCMEO 93001 20119 1740/
20118 61224 80606 0721/ 278// 123// 30718
20118 60957 81357 22015 ///// 2212/
99999

PLAIN

SOHO/LASCO observed a partial HALO CME on January 18, 2012.  Event is
first seen in C2 at 12:24 UT as faint material over the south pole which
expands the south hemisphere. The approximate width of the CME spans
pa 72-278 degrees totaling 206 degrees wide. The event continues into
the C3 field beginning 14:30-00:06 UT where it dissipates at 20 Rsun in the south.

Time/height measurements were marked at 8 points in C2 with speeds of 533.1 Km/sec
at position angle 202 degrees. The event is marked to 12 points in C3.  Speeds
average through both fields to 718.1 Km/sec at PA 191 degrees. Acceleration of
17.74 m/sec^2. 

SDO AIA 304 shows elevated material NW of AR 11399 along a filament channel
located at [S15,E20].  Material is ejected at 09:57 UT.  A ribbon flaring of the 
filament at the south end near AR 11399 begins at 11:39 UT which erupts the channel
extending to disk center. AIA 193 shows a dimming of that area with material prior
to the SDO calibration maneuvers at 14:12 UT.
STEREO: Beacon data
COR2 B,  12:55 UT loop front with cavity over south west. 
Preliminary time/height measure gives 514.8 km/sec velocity at LE.
COR2 A, 13:39 UT in progress expanding burst over south east
Preliminary time/height measure gives 536.3 km/sec velocity at LE.


The observation of this event is considered 'FAIR'. 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/2012/120118/

Best regards,

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

BT