SOHO/LASCO Halo CME 20120405

Halo Alert: halo-message.20120405

UCMEO 93001 20406 1620/
20405 62125 80506 1971/ 019// 333// 30898
20405 62021 82154 43421 11450 2112/
99999

PLAIN

SOHO/LASCO observed a partial HALO CME on April 5, 2012. Event is
first seen in C2 at 21:25 UT as a bright loop front over the west. The
approximate width of the CME spans pa 197-19 degrees totaling 182 degrees wide.
The event continues into the C3 field beginning 21:54-05:06 UT to the edge
of the field in the NW. There is a small increase of proton particles seen in the
white light images.

Time/height measurements were marked at 5 points in C2 with speeds of 813.2 Km/sec
at position angle 310 degrees. The event is marked to 9 points in C3. Speeds
average through both fields to 897.9 Km/sec at PA 312 degrees. Acceleration of
24.12 m/sec^2.

SDO AIA 193 shows a cme from AR 11450 with a flare located [N18,W29] beginning
20:57-21:54 UT with dimming and small wave west of the AR and bright post arcade.
AIA 304 shows a filament elevating/activating adjacent to AR 11450 at the north
[N21,W34] beginning 20:21 UT. As the filament erupts a flare of AR 11450 triggers
at 20:54 UT in AIA.
STEREO: Beacon data
COR2 A, 21:54 UT in 1 frame, bright loop cme beginning over the east. 21:54-03:54 UT
data gap.
EUVI A, 20:45-21:55 UT AR 11450 on limb in NE, cme with small wave. 21:55-03:55 UT gap.
COR2 B, 19:54-00:24 UT data gap. at 00:24 UT a partial halo cme over north hemisphere
in progress which is close to edge of field at first frame.
EUVI A, 20:05-22:55 UT data gap. n/a

NOAA reports a long duration C1.5 Xray flare 20:49-21:57 UT from AR11450.

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/2012/120405/

Best regards,

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

BT

[Images from original message are omitted here]

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SOHO/LASCO C2 Diff	SOHO/LASCO C3 Diff	SDO/AIA 193 A

STEREO/COR2 Behind Diff	SDO/AIA 193A Diff	STEREO/COR2 Ahead Diff

SOHO/LASCO C2	SOHO/LASCO C3	SDO/AIA 304A

	SDO/AIA 304A Diff