SOHO/LASCO Partial HALO CME 120424

UCMEO 93001 20424 2020/
20424 60800 91442 3433/ 153// 328// 40535
20424 60715 80818 18817 ///// 1112/
99999

PLAIN

SOHO/LASCO observed a partial HALO CME on April 24, 2012.  Event is
first seen in C2 at 08:00 UT with a loop surfacing on the equatorial east. 
The loop develops with cavity and core and expands with extensions to a partial
halo cme.  The approximate width of the CME spans pa 343-153 degrees totaling
170 degrees wide. There is a temporary data gap in C2, 08:48-10:24 UT.
The event continues into the C3 field beginning 08:42-14:42 UT to 18.5 Rsun
while still in progress at last frame before a DSN gap period.

Time/height measurements were marked at 5 points in C2 with speeds of 647.7 Km/sec
at position angle 86 degrees. The event is marked to 8 points in C3.  Speeds
average through both fields to 535.1 Km/sec at PA 87 degrees. Acceleration of
14.42 m/sec^2. 

SDO AIA 193 shows ejecta from an AR coming on disk with flare in the east located
[N17,E88] beginning 07:15 UT.  The flare begins 07:39-18:18 UT producing a cme with
a wave. 

STEREO: Beacon data
COR2 B,  08:24 UT, a bright loop expanding over the west.
Preliminary time/height measure gives 612.5 km/sec velocity at LE.
EUVI B, 07:25-08:45 UT, flare of AR on disk near west limb produces a cme
with wave westward.
COR2 A, 05:54-08:24 UT data gap. First frame of 18:24 UT shows an asymmetric halo.
Preliminary time/height measure gives 236.6 km/sec velocity at LE.
EUVI A, n/a

NOAA reports a C3.7 Xray flare 07:38-08:00 UT. Region not reported.

The observation of this event is considered 'GOOD'. This CME is determined a LIMB event.
Material seems to be spread across both sides of the East limb area as shown from EUVI 
and COR2 BEHIND.

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

http://umbra.nascom.nasa.gov/lasco/observations/halo/2012/120424/

Best regards,

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

BT