Date: Thu, 17 Aug 2006 08:17
From: Guillermo Stenborg
Subject: b) Strong Asymmetric Full Halo Event on 2006/08/16, frontsided
Status: O
UCMEO 93001 60817 1220/
60816 61630 92342 0001/ 360// 113// 30915
60816 61437 81922 30816 10904 1212/
99999
PLAIN
This is the report corresponding to the second Halo Event observed by
LASCO/EIT on 2006/08/16. The event was first seen in C2 at 16:30 UT all
above the S Pole as a bright and wide loop front, the LE already half way
to the end of the C2 FOV (note that there is a C2/C3/EIT 195 Full Field
data gap between around 14:30 and 16:30 UT due to EIT/CDS ICAL01
-Intercalibration for EIT with CDS- between 15:00 - 16:20 UT). By 17:30
UT, the LE of the event is already past the outer edge of C2, and diffuse
extensions all around the outer edge of the event fully cover the
occulting disk. The event was first seen in C3 at 16:42 UT appearing about
the S Pole. By 19:42 UT the C3 occulting disk is fully covered (signal on
N just above the occulting disk). The mean plane-of-sky speed of the
outermost front of the event (it becomes very diffuse by the end of the
C3 FOV) at PA 175 was ~ 915 km/sec (based on C3 data), showing a slight
acceleration.
GOES reported a long duration C3.6 X-ray flare on NOAA AR 10904 (S16W08)
between 14:37 - 19:22 UT with peak emission at 16:17 UT.
EIT 195 images show a brightening on AR 10904 starting at 16:24 UT,
peaking at around 17:12 UT. Nice post-flare loops. Formation of a dimming
region all around the AR, most discernible to S of AR.
In summary, the event has therefore been determined as an intense
asymmetric full Halo Event, frontsided, associated with the C3.6 LDE on
AR 10904.
LASCO/EIT movies and images of the event will shortly be made available
at:
ftp://ares.nrl.navy.mil/pub/lasco/halo/20060816b
NOTE:
There will not be LASCO C2/C3 CME watch during 2006/08/17 and 08/18 due
to a special Observation campaign with EIT (7 minute high cadence run in
304A until 08/18 22:00 UT, afterward CCD EIT Bakeout).
Best wishes,
Guillermo Stenborg
++
Dr. Guillermo A. Stenborg
SOHO-LASCO Operations Scientist,
CUA, MC 612.5, Bldg 26, Rm 001, F: +1-301-286-0264
NASA Goddard Space Flight Center,
Greenbelt, MD 20771. P: +1-301-286-2941
e-mail: stenborg@kreutz.nascom.nasa.gov
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