From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Nov 21 2003 - 09:02:38 PST
----- Original Message -----
From: Cary Oler
Sent: Thursday, November 20, 2003 7:25 PM
To: sun-earth_at_SkyandTelescope.com
Subject: AstroAlert: Severe Geomagnetic and Auroral Storm is In-Progress !
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This Is SKY & TELESCOPE's AstroAlert for Sun-Earth Interactions
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A s t r o A l e r t
Sun-Earth Alert
Solar Terrestrial Dispatch
http://www.spacew.com
20 November 2003
SEVERE GEOMAGNETIC AND AURORAL STORM IS IN-PROGRESS
Effects of a complex coronal mass ejection on 18 November are
responsible for producing a large geomagnetic and auroral storm on 20
November. The disturbance has been associated with unusually intense magnetic
fields in space. The Earth's magnetopause (the boundary between the calm
conditions inside the Earth's magnetic shield and conditions outside in the
solar wind) has been eroded by these interplanetary magnetic fields to the
point that geosynchronous orbiting spacecraft are crossing through the
magnetopause boundary as they swing toward their noon-time orbital positions
between the Earth and the Sun. This is not uncommon for strong disturbances
and simply illustrates the influence that the magnetic fields can have when
they come in contact with the Earth's own magnetic field. Magnetopause
crossings can cause problems for spacecraft that are dependent upon the
Earth's magnetic field to determine their orientation. They can also expose
the spacecraft to more hazardous conditions that can shorten spacecraft
and/or instrument lifetimes.
The location of the auroral ovals have migrated substantially
equatorward. This means that locations that are normally far from the auroral
oval may be located inside the oval. As a result, the potential for observing
periods of moderate to strong auroral storm activity exists for a large area
of the middle and low latitude regions.
The areas that are particularly well placed are those in New Zealand and
Australia and Europe. The arrival of the disturbance provided western North
America with a powerful show (bright red auroral activity visible well into
the United States). Unfortunately, sunrise quickly extinguished attempts to
view activity from the eastern regions.
The disturbance probably won't have the duration to last through to
nightfall in North America. Nevertheless, storms of this strength usually
produce sporadic periods of visible auroral activity well into the middle
latitude regions even during the declining phase of the activity. So it might
be well worth the effort to take a moment and look skyward tonight even if
conditions might not appear favorable.
A low latitude aurora warning has been issued as well as a middle
latitude aurora warning. Areas from the central U.S. northward and the
northern tier of countries (including France through Germany and central
Russia) should be aware of the increased possibility of auroral activity
tonight. New Zealand and the southern regions of Australia should also be
alert for possible activity.
Please report any observations of activity to the auroral activity
observation network at: www.spacew.com/submitsighting.html
It is interesting to note that the sunspot complex that produced this
strong disturbance (Region 501) also spawned a major solar flare during the
last 24 hours. The jury is still out with respect to the potential impact the
associated coronal mass ejection might have on the Earth. Perhaps another
round of activity will grace the skies in the coming days. Stay tuned.
** End of the AstroAlert Bulletin **
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