SOHO/LASCO HALO CME 120327ab

UCMEO 93001 20327 2130/
20327 60312 80818 3031/ 302// 223// 40861
20327 60248 80312 41421 11444 1212/
99999

PLAIN

SOHO/LASCO observed two (2) HALO CMEs on March 27, 2012 close in time. The first
event is seen in C2 beginning 03:12 UT as bright material over the  North Pole.
A faint edge of material expands along with the leading material to a full halo
cme by 04:12 UT.  A second event following is seen in C2 beginning 04:36 UT.
The system expands with faint extensions as a full halo by 05:24 UT.
The first event begins in the C3 field 03:30 UT followed by the second lines at 
04:42 UT. Events exit the C3 field at 08:18 UT at 30 Rsun in the North.

Time/height measurements:
Event (1) marked to 5 points in C2 with speeds of 983.7 Km/sec
at position angle 303 degrees. The event is marked to 11 points in C3.  Speeds average
through both fields to 860.5 Km/sec at PA 304 degrees.  Acceleration -11.31 m/sec^s.
Event (2) marked to 5 points in C2 with speeds of 644.3 Km/sec.
The event is marked to 9 points in C3.  Speeds average through both fields
to 679.3 Km/sec at PA 306 degrees.  Acceleration -4.80 m/sec^s.

SDO/AIA 193 and 304 show a flare of AR 11444 located near disk center at [N21,W14]
beginning 02:48-03:12 UT with a cme.  Core material is emitted northward.  A brightening
of AR 11444 starts at 04:00 UT with small emission as adjacent filament material
erupts at the southern area of the AR at 04:36 UT.

STEREO: Beacon data
COR2 A, 3/26 16:54-04:24 UT data gap. First frame after data gap at 04:12 shows
a cme in progress near the edge of the FOV in East and North East.
EUVI A, 3/26 16:45-04:15 UT data gap.  n/a
COR2 B, 03:25 UT, expanding cme in North and North West. A second loop follows the
first event beginning 04:55 UT
Preliminary time/height measure of first LE gives 702.2 km/sec velocity at pa 299 degrees.
EUVI B, Material over the NW limb with northward projection 02:56-03:16 UT, seen in diff.

NOAA reports a C5.3 Xray flare of AR 11444 02:50-0322 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/2012/120327ab/

Best regards,

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

BT