SOHO/LASCO HALO CME 110809a

UCMEO 93001 10809 1600/
10809 60812 81518 2771/ 276// 223// 41632
10809 60748 80827 46917 11263 1112/
99999

PLAIN

SOHO/LASCO observed a HALO CME on August 9, 2011.  Event is
first seen in C2 at 08:12 UT with bright impulsive front over the West
at the equator. The material expands with extensions to a full HALO by 09:24 UT.
The event continues into the C3 field beginning 08:30 to 15:18 UT at 30 Rsun.
This SEP event produced proton particles seen in the LASCO white light images. 

Time/height measurements were marked at 2 points in C2 with speeds of 2309.0 Km/sec
at position angle 277 degrees. The event is marked to 6 points in C3 where it slightly
slows.  Speeds average through both fields to 1631.7 Km/sec at PA 280 degrees, 
acceleration n/a. 

SDO/AIA 193 shows a flare of AR 11263 07:51-08:27 UT located at [N17 W69] with a
progressive wave over the entire west hemisphere.  
STEREO:
COR2 A, 08:24 UT, in east, expanding to a full HALO out to 12 Rsun FOV.
Preliminary height/time measure was taken on COR2 beacon data showing 1920.9 km/sec
EUVI 195 A, flare 08:05-08:45 of AR 11263 on disk in East with wave progressing
west and east directions.
NOAA reports a X6.9 xray flare of AR 11263 07:48-08:08 UT.  An increase in proton 
flux in the 100 MeV levels, event enters solar storm threshold.

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/2011/110809a/

Best regards,

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

BT