Subject: SOHO/LASCO HALO CME 140120b

UCMEO 93001 40121 1730/
40120 62212 80418 1521/ 151// 333// 30638
40120 62136 82315 26505 ///// 2212/
99999

PLAIN

SOHO/LASCO observed an asymmetric HALO CME [B] on January 20, 2013.  Event
is first seen in C2 beginning 22:12 UT with a bright loop over the East.
The event expands with extensions to a full HALO with cavity and core by
23:48 UT.  The event continues into the C3 field beginning 22:30-04:18 UT
leaving the C3 field at 30Rsun in the East. 

Time/height measurements were marked at 3 points in C2 with speeds of
702.3 Km/sec at PA 152 degrees. The event is marked to 11 points in C3.  
Speeds average through both fields to 637.6 Km/sec at PA 152 degrees.
Acceleration -31.43 m/sec^2. 

SDO/AIA 193A and 304A shows an eruptive filament 21:36-23:15 UT at
location centered [S05, E65] West of and adjacent to (soon to be)
AR11963.  A post loop arcade follows the eruption.

STEREO: BEACON data
COR2 A,  22:24 UT begins a CME in the West in 1 frame before DSN gap.
Preliminary time/height measure: n/a
EUVI A 195, n/a
COR2 B, 21:55 UT data gap begins.
EUVI B 195, 21:26 UT shows a CME over the limb in the West.

GOES shows a long duration  C3.6 Xray flare 21:39/22:49/23:57 UT from 
AR 11963 at location [S07, E67].  

The observation of this event is considered 'FAIR'. This CME is determined FRONTSIDE.

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

http://umbra.nascom.nasa.gov/lasco/observations/halo/2014/140120b/

Best regards,

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

BT