Subject: SOHO/LASCO HALO CME 120307b

UCMEO 93001 20307 1700/
20307 60136 80430 0901/ 089// 333// 32544
20307 60106 80130 12117 11429 1112/
99999

PLAIN

SOHO/LASCO observed two (2) HALO CMEs on March 7, 2012.  The second event is seen in
C2 at 01:36 UT as an impulsive loop following a previous event (halo).
The event continues into the C3 field beginning 01:42 to 04:30 UT
out to 30 Rsun as it leaves the field of view in the East. Proton emission is seen
heavy in LASCO data.

Time/height measurements were marked [20120307b2] to 2 points in C2 with speeds of 2182.2 Km/sec
at position angle 95 degrees. The event is marked to 6 points in C3. Speeds average
through both fields to 2543.9 Km/sec at PA 90 degrees.  Acceleration -49.03 m/sec^2.

SDO/AIA 193 shows a flare of AR 11429 located at [N17,E21] beginning 01:06-01:30 UT.
A dimming is seen with a wave.  Activation between the west area of AR 11429 and 11430
produces a darkening south of the ARs with emission 01:12-01:42 UT.

STEREO: Beacon data
COR2 B, 3/6 21:25-01:25 UT data gap. Beginning 01:25 UT a full asymmetric halo
over the west field.  Leading edge is out of the field in first frame after gap.
EUVI B, 3/6 21:36-01:26 UT data gap. n/a
COR2 A, 3/6 22:39-05:24 UT data gap. n/a
EUVI A, 3/6 22:45-04:55 UT data gap. n/a

NOAA reports a X1.3 Xray flare of AR 11429 01:05-01:23 UT.
An SEP event with proton flux of >100 MeV above solar storm levels.

The observation of this event is considered 'FAIR'. 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/2012/120307ab/

Best regards,

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

BT