Halo CME Mail

Date: Fri, 6 Apr 2001 12:13:36 -0400 (EDT)

From: Gareth Lawrence

Subject: Full halo CME on 2001/04/05

  ------------------------------------------------------------------------

UCMEO 93001 10405 1700/
10405 61706 92118 0001/ 360// 223// 41046
10405 61648 91812 25024 09415 1112/
99999

PLAIN

BT

LASCO and EIT observed a full halo CME on 2001/04/05. The event
was first observed in C2 at 16:48 UT as a bright wide front from
the NE to SE. The C2 occulting disk was surrounded by 17:24 although
emission over the N pole was faint. The bright front first appeared
in C3 at 17:42 with the C3 occultor surrounded by 18:18. The plane
of sky speed of the fastest region of the front was measured as
1046 km/s at PA 83 (W) with no significant deceleration.

The most probable source of the CME was an M5.1 X-ray flare in
AR 9415, plus other associated activity. GOES records the flare
between 16:57 and 18:14 UT with peak emission at 17:25. The flare
was observed in EIT from 16:48 to 18:24 with peak emission
at 17:24. An EIT wave was observed during the event, as was
dimming. A large CME was observed by EIT with the greater part
of the ejection apparently originating somewhat to the E of the
AR, nearer the limb. This is consistent with the bright front
over the E limb and fainter emissions elsewhere, but the EIT
data shows enough activity on the disk to suggest that the CME
may have a significant Earth-directed component.

Images and movies of this event are available at:

ftp://ares.nrl.navy.mil/pub/lasco/halo/20010405

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       |
++