SOHO/LASCO HALO CME 120723

UCMEO 93001 20723 1720/
20723 60236 80518 2682/ 267// 333// 42142
20723 60145 80255 ///// 11520 1112/
99999

PLAIN

SOHO/LASCO observed a HALO CME on July 23, 2012.  Event is first seen in C2 at
02:36 UT as a bright loop over the west with leading edge at 3Rsun.  The event
develops with extensions to a full asymmetric HALO (west) by 03:12 UT. The event
continues into the C3 field beginning 02:42-05:18 UT out to the edge of field at
30 Rsun in the West.

Time/height measurements were marked at 2 points in C2 with speeds of
1891.3 km/sec at position angle 268 degrees. The event is marked to
8 points in C3.  Speeds average through both fields to 2142.3 Km/sec
at PA 268 degrees. Acceleration of -5.41 m/sec^2. 

SDO AIA 193 shows a CME coming from behind the limb in the west 02:12-02:39 UT.
Wave material from the far side event is shown in the SW quadrant on the 193
difference images.

STEREO: BEACON data
COR2 A,  02:39-0439  UT, symmetric halo.  Large proton flux increase in COR2A. 
Preliminary time/height measure gives 1464.8 km/sec velocity at LE.
EUVI A 195, 01:45-02:55 UT,  flare of AR 11520 on disk near central meridian
located [S17,W141]. The event produces a wave.  Increased proton flux in EUVI 195 field.
COR2 B, 00:54-07:24 data gap.  n/a
EUVI B 195, 00:56-06:55 data gap.  n/a

GOES13 shows an instant increase in proton flux with particles >100MeV.  Particles
in the 10MeV range peak above storm levels.

The observation of this event is considered 'GOOD'. This CME is determined a LIMB event.
Material is transfered on the face of the disk in the SW.

Images and movies and time/height information for this event is available on the web at:

http://umbra.nascom.nasa.gov/lasco/observations/halo/2012/120723/

Best regards,

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

BT