Halo CME Mail

Date: Wed, 5 Jun 2002 17:40

From: Gareth Lawrence

Subject: Partial Halo CME on 2002/06/05, probably frontsided

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UCMEO 93001 20605 2300/
20605 71218 91842 0551/ 310// 213// 40885
20605 60801 90946 22433 09979 2222/
99999

PLAIN

BT

LASCO and EIT observed a partial halo CME on 2002/06/05. The
event was first observed already in progress in C3 at 12:18 UT
when observations were restarted following the weekend
maneuvers. A wide, moderately faint front could be seen at
~13 Rs, spanning ~255 deg from PA 55-310. Brighter material
was seen trailing, and there may have been faint extensions
in the N. The mean plane of sky speed of the front was measured
as 885 km/s at PA 152 (SE) with moderate acceleration; however
these numbers were calculated for a faint feature in a limited
dataset. The CME was completely clear of the C2 field of view
when observations resumed.

GOES does not record any significant X-ray events from the
frontsided disk all morning, and EIT activity was relatively
low. However, difference movies clearly show a sizeable CME
in the SE between 08:01 - 09:46 UT from, or slightly to the
E of, AR9979. The disturbance was centred on S32E24. Neither
a wave nor dimming were observed in association with this
event, and the CME appeared to be largely directed to the S
and E of the eruption.

Extrapolating the above speed and acceleration back to 1 Rs
gives a time that is roughly consistent with the EIT CME,
despite the apparent location and direction of the EIT event.
In light of the data coverage and these ambiguities this event
has been determined to be probably frontsided with a possible
earth-directed component.

Images and movies of this event are available at:

ftp://ares.nrl.navy.mil/pub/lasco/halo/20020605

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       |
++