Halo CME Mail

Date: Sun, 21 Apr 2002 16:09:06 +0000 (GMT)

From: Kevin Schenk

Subject: Partial HALO CME on 2002/04/21

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UCMEO 93001 20421 1600/
20421 60127 90342 1401/ 042// 333// 42427
20421 70048 80248 31484 09906 1122/
99999
BT

EIT and LASCO observed a partial HALO CME on 2002/04/21.  The event was
first seen in the Lasco C2 field beginning 01:27 UT as a bright dual loop
front into the field at 4Rs.  This extremely fast front was followed by
cavity and core with material spanning the West hemisphere, PA 140-42
degrees.  The event entered the C3 field at 01:42 with acceleration and
was tracked to 28Rs with a plane-of-sky speed averaged through both fields
to 2427 km/sec at PA 273.  Large proton flux is seen in white light
images.

EIT observed multi events contributing to the CME witnessed in the Corona.
Beginning 00:12 UT a CME from AR 9907 located at [S03; W56] takes off with
West direction.  By 00:48 UT a flare starts in AR 9906 at location
[S14;W84] which produces a NW,SE EIT wave and triggers a filament channel
eruption at 01:48 UT East with SE direction at location [S17;W58].  Bright
post event arcade follows. This in total produced a complex CME event with
large emission.  Proton flux is seen in the EUV images.

GOES shows a long duration M1.5 class x-ray flare between 00:43-02:38 UT.
This event is probably related to the events seen in LASCO.

Images and movies are available on the ftp server at:

ftp://ares.nrl.navy.mil/pub/lasco/halo/20020421/

note: we have been notified of some download problems with the images and
movies.  This seems to be due to security upgrades and the use of older
versions of Netscape and IE below versions 6. We are still working on
this. We applogize for the inconvenience if any.

Best reguards,

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