Subject: SOHO/LASCO HALO CME 120305

UCMEO 93001 20305 1930/
20305 60400 90618 0481/ 047// 333// 41587
20305 60333 80424 15217 11429 1112/
99999

PLAIN

SOHO/LASCO observed a HALO CME on March 5, 2012.  Event is first seen in
C2 at 04:00 UT as a loop with cavity and core over the NE limb which 
expands with extensions to a full halo CME by 04:36 UT.
The event continues into the C3 field beginning 04:06 to 06:18 UT out to 21.5 Rsun
at last frame before a temporary data gap.

Time/height measurements were marked to 3 points in C2 with speeds of 1440.3 Km/sec
at position angle 48 degrees. The event is marked to 8 points in C3. Speeds average
through both fields to 1587.4 Km/sec at PA 48 degrees.  Acceleration 9.23 m/sec^s.


SDO/AIA 193 shows a CME beginning at 03:27 UT prior to a flare of AR 11429 located
at [N17,E52] beginning 03:33-04:24 UT.  A dimming is seen west, south west of the AR
and a wave propagates in the upper west and north hemispheres followed by a  post loop
arcade.

STEREO: Beacon data
COR2 B, 3/4 22:55-02:40 UT data gap. Beginning 03:40 UT an expanding loop CME with cavity
and core develops to a full halo by 04:55 over the west hemisphere.
Preliminary time/height measure gives 1177.7 km/sec velocity at LE. 
EUVI B, 03:36-04:56 UT flare with CME from AR (11429) near NW limb with wave over
the west hemisphere.
COR2 A, 3/4 21:54-05:39 UT data gap.  After data gap an asymmetric halo is seen
in progress.
EUVI A, 3/4 21:54-05:45 UT data gap.

NOAA reports a X1.1 Xray flare of AR 11492 02:30-04:43 UT.
   
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/2012/120305/

Best regards,

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

BT