Subject:  SOHO/LASCO Partial HALO CME 110709

UCMEO 93001 10711 1830/
10709 60048 80618 3351/ 206// 223// 40604
10708 62315 80430 22419 11247 2112/
99999

PLAIN

SOHO/LASCO observed a Partial HALO CME on July 9, 2011.  Event is first seen in
C2 at 00:48 UT as faint rough LE loop at PA 122 degrees. The front expands with
extensions PA 335-266 degrees for a total coverage of 231 degrees over the
East hemisphere. The event continues into the C3 field beginning 01:42 to
06:18 UT out to 18.3 Rsun where it dissipates. The material looks to be the
result of 2 emissions.

Time/height measurements were marked at 6 points in C2 with speeds of 517.5 Km/sec
at position angle 122 degrees. The event is marked to 9 points in C3 where it
accelerates.  Speeds average through both fields to 604.4 Km/sec at PA 117 degrees.
Acceleration of 12.00 m/sec^s.

SDO/AIA 193 shows an eruption of the filament along side of AR 11247 in the SE [S19, E24]
beginning 7/08 23:15-01:45 UT with a wave expanding from center.  AIA 304 sees this
eruption with a slow propagation of material through 04:30 UT. Another small filament
eruption in the North 50 deg near centeral meridian at 03:27 UT. 
STEREO EUVI B beacon data shows a flare with cme on the NE limb  22:13-23:38 UT and a
filament eruption beginning 23:13 UT in the SW on disk near limb.
COR2 B cme beginning 00:54 UT with large expanding burst over W/SW with core.  This
is the bulk of the CME.

This is most probably the cause of the Partial HALO event seen in LASCO.

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/2011/110709/

Best regards,

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

BT