Subject: SOHO/LASCO Partial HALO CME 120717

UCMEO 93001 20717 2030/
20717 61348 91730 1531/ 304// 333// 40814
20717 61215 81606 36123 11520 1212/
99999

PLAIN

SOHO/LASCO observed partial HALO CME on July 17, 2012.  Event is first
seen in C2 at 13:48 UT as a bright loop with cavity and core in the 
South West. The approximate width of the CME spans pa 153-304 degrees
totaling 151 degrees wide. The event continues into the C3 field
beginning 14:42 to 17:30 UT at 17.7 Rsun at last frame in progress.

Time/height measurements were marked to 8 points in C2. 
The event is marked to 14 points in C3. Speeds average through both fields
to 813.5 Km/sec at PA 240 degrees.  Acceleration 71.06 m/sec^2.


SDO/AIA 193 and 304 show a flaring of a filament channel centered [S23,W61]
east and adjacent to AR 11520 beginning 12:15-16:06 UT and finishing with
bright post arcade.  

STEREO: Beacon data
COR2 A, 13:54-15:54 UT last frame before gap. Bright loop over the SE. 
Preliminary time/height measure gives 802.0 km/sec velocity at LE. 
EUVI A, 12:55-15:55 UT last frame before gap. AR 11520 on disk in SE
produces a cme with post arcade.
COR2 B, 14:39-17:54 UT.  Bright loop with cavity and core expanding over
south hemisphere.
Preliminary time/height measure gives 694.7 km/sec velocity at LE.
EUVI B, n/a.

NOAA reports a M1.7 Xray flare of AR 11520 12:03-19:04 UT.
An instant increase in proton flux is shown, particles at >10 MeV peaked above
storm level conditions. 
   
The observation of this event is considered 'GOOD'. 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/2012/120717/

Best regards,

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

BT