Halo CME Mail

Date: Fri, 21 Sep 2001 17:44

From: Gareth Lawrence

Subject: Partial Halo CME on 2001/09/20

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UCMEO 93001 10919 2230/
10920 61931 90242 2401/ 040// 113// 30453
10920 61812 91848 41109 09631 1222/
99999

PLAIN

BT

LASCO and EIT observed a partial halo CME on 2001/09/20. The
event was first observed in C2 at 19:31 UT as a wide loop front
in the NW. By 20:06 UT this front spanned some 160 deg over the
N Pole from PA 240 to PA 40. The front first appeared in C3 at
20:18 UT with maximal coverage of the C3 occultor by 21:18 UT.
The plane of sky speed of the front was measured as 453 km/s at
PA 273 (W) with no significant acceleration through the
coronagraphs' fields of view.

The CME was most probably associated with an M1.5 X-ray flare in
AR9631 between 18:12 and 18:21 UT with peak emission at 18:17.
EIT also observed this flare between 18:12 and 18:24, peaking at
18:12. SEC places the flare at N09W11 and the disruption was
largely localised to the immediate vicinity of this region. No
significant dimming or wave was observed in association with this
event. Bright post-eruption loops are clearly visible at a later
time.

Images and movies of this event are available at:

ftp://ares.nrl.navy.mil/pub/lasco/halo/20010920

and note that the C3 movie in particular shows significant
ejecta in the NE and SW from earlier, distinct events.

Best wishes,
        Gareth Lawrence.

++
| Gareth Lawrence,                   E-mail:grl@kreutz.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       |
++