Subject: SOHO/LASCO HALO CME 131025a

UCMEO 93001 31025 1940/
31025 60824 81554 0961/ 095// 233// 40739
31025 60754 80821 27308 11882 1122/
99999

PLAIN

SOHO/LASCO observed an asymmetric HALO CME on October 25, 2013.  Event is first
seen in C2 at 08:12 UT as a bright loop in the East limb.  The event expands
to full HALO by 10:12 UT. The event continues into the C3 field beginning
08:42 to 15:54 UT where it exits the field of view at 30Rsun in the East.

Time/height measurements were marked to 3 points in C2 with speeds of 714.8 Km/sec
at position angle 96 degrees. The event is marked to 7 points in C3.  Speeds average
through both fields to 739.0 Km/sec at PA 96 degrees.  Acceleration 22.63 m/sec^2.


SDO/AIA 193A shows a flare from a region near the East limb at location [S08, E73]
from AR 11882 beginning 07:54-08:21 UT.  A wave is seen propagating across the East
hemisphere.

STEREO: BEACON Data
COR2 A, 08:239-12:54 UT, loops over the SW expands to an asymmetric halo. 
Preliminary time/height measure gives 496.4 km/sec velocity at LE.
EUVI A, n/a.
COR2 B, 16:25-10:25 UT data gap. A CME is seen in progress over the West.
Preliminary time/height measure gives 464.1 km/sec velocity at LE.
EUVI B, 16:16-10:06 UT data gap. n/a.

NOAA reports a X1.7 Xray flare 07:53/08:01/08:09 UT from AR 11882 at location [S04, E72].

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/2013/131025a/

Best regards,

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

BT