Subject: SOHO/LASCO HALO CME 120328 BACKSIDED

UCMEO 93001 20328 1930/
20328 60136 80730 0482/ 047// 333// 31027
20328 60056 80236 ///// 11429 1212/
99999

PLAIN

SOHO/LASCO observed a HALO CME on March 28, 2012.  Event is first seen
in C2 at 01:36 UT with a bright loop compressed over the Northeast limb
following ejecta released from the area at 00:16 UT. The event expands 
with extensions to a full halo by 02:48 UT. The event continues into the
C3 field beginning 02:06 to 07:30 UT leaving the C3 field at 30 Rsun in
the Northeast.

Time/height measurements were marked to 6 points in C2 with speeds 
of 853.7 Km/sec at position angle 48 degrees. The event is marked to 11 points 
in C3. Speeds average through both fields to 1027.1 Km/sec at PA 48 degrees.  
Acceleration 27.15 m/sec^2.

SDO/AIA 193 and 304 shows the 2 part event of ejecta beginning 00:15 UT
and the large cme liftoff behind limb over the East and North hemispheres.

STEREO: Beacon data
COR2 B, 01:55 UT core material rises north, cme expands 02:25 UT with flank
West.  02:55-06:40 UT data gap.
EUVI B, 00:16-00:66 UT cme with core from AR 11429(?) northward followed
closely by large cme with dimming across the North hemisphere 00:56-02:36 UT.
COR2 A, 3/27 20:54-04:24 UT data gap.  First frame 04:24 UT halo cme already
out of the COR2 FOV.
EUVI A, 3/27 21:05-04:15 UT data gap.  n/a

   
The observation of this event is considered 'FAIR'. This CME is determined a BACKSIDED 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/2012/120328/

Best regards,

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

BT