Halo CME Mail

Date: Mon, 19 Mar 2001 12:44

From: Gareth Lawrence

Subject: Full halo CME on 2001/03/19

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UCMEO 93001 10319 1730/
10319 60526 91242 0001/ 360// 113// 4268
10319 60324 90736 30704 0//// 2212/
99999

PLAIN

BT

LASCO and EIT observed a faint full halo CME on 2001/03/19. The event
was first observed in C2 at 05:26 UT as a wide loop front over the NW
limb. At 06:26 this front extended from about PA 150 to PA 45, with
fainter extensions around the eastern portion of the C2 occulting
disk. As a result of an earlier CME over the E limb and the image
differencing process used, it is hard to see this faint material in
the images and movies. The north-westerly front first appeared in C3
at 07:18 and the C3 occulting disk was surrounded by 08:18. The
plane-of-sky speed of the leading edge through to about 15 Rs was
about 268 km/s at PA 318 (NW limb).

The CME was probably associated with an eruptive filament observed near
disk center by  EIT between 03:24 and 07:36 UT on 2001/03/19. The center
of the region first visibly affected was S04W07 and the greater part of
EIT activity appeared somewhat to the N of this, consistent with the
first appearance of the CME over the NW limb. This site of origin was
to the N and W of AR 9376. No GOES events above background level are
listed around the time of this event, and no events are seen peaking
above C1 level during the morning.

Images and movies of this event are available at:

ftp://ares.nrl.navy.mil/pub/lasco/halo/20010319

Please note that the CME is quite hard to discern in the C3 images and
movies due to earlier activity and the faint nature of the event. However,
the front expands rather symmetrically, which may aid identification.

Best wishes,

        Gareth Lawrence.

++
| Gareth Lawrence,                 E-mail:grl@ajcannon.nascom.nasa.gov |
| SOHO-LASCO Operations Scientist,                                     |
| CUA, Mail Code 682.3,                                                |
| NASA Goddard Space Flight Center,      Phone:  +1-301-286-2941       |
| Building 26, Room G-1,                         +1-301-286-3447       |
| Greenbelt, MD 20771.                   Fax:    +1-301-286-0264       |
++