SOHO/LASCO HALO CME 120831

UCMEO 93001 20902 2050/
20831 62000 80006 1111/ 110// 333// 31167
20831 61924 82130 25019 11563 2112/
99999

PLAIN

SOHO/LASCO observed a full  asymmetric HALO CME on August 31, 2012.  Event is first seen
in C2 beginning 20:002 UT with a bright loop with cavity and core over the SE.  The event 
expands with extensions to a full halo by 20:48 UT.  The event continues into the
C3 field beginning 20:18-00:06 UT out to the edge of field at 30 Rsun in the Southeast.

Time/height measurements were marked at 4 points in C2 with speeds of
1063.1 Km/sec at pa 111 degrees. The event is marked to 9 points in C3.  
Speeds average through both fields to 1166.7 Km/sec at PA 111 degrees.
Acceleration -22.19 m/sec^2. 

SDO AIA 193 shows activation of a filament at 18:51 UT with location centered at [S19,E50].
A dual ribbon flare event.  The filament erupts by 19:24-20:48 UT adjacent to and south of
AR11562 and adjacent to AR11563 along the NE while finishing with bright post arcade.  
A flare of AR11563 is triggered and observed beginning 20:18 UT.  A dimming and wave are
produced with material spanning the east hemisphere.
SDO AIA 304 shows the eruptive filament, material continues to span the face of the disk
with dimming until 09:30 UT.

STEREO: BEACON data
COR2 B, 18:25-22:25 UT Data gap. Asymmetric halo already to edge of FOV in first frame.
EUVI B 195, 18:36-22:26 UT data gap.  n/a
COR2 A,  16:24-02:24 UT Data gap. n/a
EUVI A 195, 16:35-02:05 UT Data gap. n/a


NOAA reports a long duration C8.1 Xray flare 19:45-20:43-21:51 UT from AR 11563 at location [S25,E59]

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

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

http://umbra.nascom.nasa.gov/lasco/observations/halo/2012/120831/

Best regards,

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

BT