Subject: SOHO/LASCO HALO CME 130411

UCMEO 93001 30411 1640/
30411 60724 81254 0821/ 081// 323// 50986
30411 60657 80724 11209 11719 1112/
99999

PLAIN

SOHO/LASCO observed a symmetric HALO CME on April 11, 2013.  Event is first seen in
C2 at 07:24 UT as a bright loop on the East expanding to a full HALO at the
second frame with cavity and core material over the East. 
The event continues into the C3 field beginning 07:42 to 12:54 UT leaving the C3
field of view at 30Rsun. Increased proton particle emission is seen in the LASCO
fields.

Time/height measurements were marked to 3 points in C2 with speeds of 1237.1 Km/sec
at position angle 82 degrees. The event is marked to 9 points in C3.  Speeds average
through both fields to 985.8 Km/sec at PA 82 degrees.  Acceleration -27.13 m/sec^s.


SDO/AIA 193 shows a flare of AR 11719 located [N09, E12] beginning 06:57-07:24 UT.
The flare produces a dimming and wave which propagates the face of the disk
followed by a post loop arcade of the region.

STEREO: BEACON Data
COR2 A, 07:24-09:54 UT expanding asymmetric halo CME (East).
Preliminary time/height measure gives 972.8 km/sec  velocity at LE. 
EUVI A, 07:15 UT CME behind limb in the East.
COR2 B, 07:24-09:54 UT expanding partial halo CME over the West hemisphere
with SEP increases in the field of view.
Preliminary time/height measure gives 1045.3 km/sec velocity at LE.  
EUVI B,  A CME over the West limb beginning 07:06-07:26 UT.

NOAA reports an M6.5 Xray flare 06:55/07:16/07:29 from AR 11719
at location [N09, E12].  GOES13 shows a proton flux increase up to the 100MeV
levels with flux of the 50Mev above solar storm conditions.     

The observation of this event is considered 'EXCEPTIONAL'. 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/2013/130411/

Best regards,

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

BT