Subject: SOHO/LASCO Partial HALO CME 110329 BACKSIDED

UCMEO 93001 10330 1630/
10329 62024 80206 3582/ 203// 333// 41173
10329 61955 82105 ///// ///// 4112/
99999

PLAIN

SOHO/LASCO observed a Partial HALO CME on March 29, 2011.  Event is first seen in
C2 at 20:24 UT as a bright loop centered at PA 70 degrees followed by a deep
cavity.  The impulsive front expands with extensions PA 358-203 degrees for a total
coverage of 205 degrees over the Eastern hemisphere. The event continues into the
C3 field beginning 21:11 UT to 02:06 UT out to the edge of field, 30 Rsun.

Time/height measurements were marked to 4 points in C2 with speeds of 1075.2 Km/sec
at position angle 86 degrees. The event is marked to 9 points in C3 where it
slightly accelerates.  Speeds average through both fields to 1172.9.0 Km/sec at
PA 83 degrees.

STEREO EUVI 195 Behind shows an eruption of an AR in the NE beginning 19:55 - 21:05 UT
with dimming and symmetric wave.
STEREO COR2 B shows a partial halo over it's NE field beginning 20:54 UT.
SDO/AIA 193 sees a cme from the AR over the NE limb beginning 19:59 UT.
These events are most probably the cause of the HALO event seen in LASCO.

The observation of this event is considered 'GOOD'. 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/2011/110329/

Sam Freelands events page for this event is available with good information and found here:

http://sdowww.lmsal.com/sdomedia/ssw/ssw_client/data/ssw_service_110329_221908_25547/www/

Best regards,

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

BT