INTENSE SOLAR FLARING CONTINUES

A heads up on the 'big solar flare' post, this is from astroalert today, looks like there is a good chance of high aurora activity over the next week to ten days Keith..

A s t r o A l e r t

09 September 2005

Solar Terrestrial Dispatch
www.spacew.com


INTENSE SOLAR FLARING CONTINUES

Active sunspot complex 10808 (also known as Region 808) continues to
impress. It is now more fully in-view and is presenting itself as a very
large sunspot complex that will (if its present size persists) be visible to
the unaided (protected) eye over the next week to 10 days. Aside from the
very large class X17 flare reported in the last Astroalert, it has managed to
produce two additional major flares: a class X5 and a smaller class X1 within
six hours of each other (the X5 occurred at 21:06 UTC [5:06 pm EDT] on 8
September, and the X1 occurred at 03:00 UTC on 9 September [11 pm EDT on 8
September]).

Region 10808 appears to be a magnetically complex monster, with at least
one very probable strong delta magnetic configuration visible (opposite
polarity umbrae located within a single penumbra). Such configurations are
inherently less stable and are often associated with energetic solar flares.
There is obvious strong magnetic shear visible in solar images of this region
at various wavelengths that are undoubtably contributing to the energetic
events. No significant change has been observed in the sunspot complex during
the last 24 hours. Granted, it would be difficult to discern significant
changes given its close proximity to the solar limb, but there is sufficient
data available now to suggest that additional very strong solar flare
activity will likely persist in the form of moderate to strong X-class
events.

These recent events (the three X-class flares observed thus far) have
elevated the population of energetic protons in the near-Earth space
environment to levels that are now roughly 100 times more dense than normal
background levels. Energetic protons are being redirected by the Earth's
magnetic field toward the polar ionospheres, where they are bombarding and
ionizing the polar ionosphere to levels sufficient to produce a phenomenon
known as Polar Cap Absorption (or PCA). PCA is not harmful to human health,
but can be dissasterous to high-frequency radio communications through the
polar regions. Such radio signals are normally bounced off the lower side of
the ionosphere and are returned back to the Earth, permitting long-distance
radio communications to take place. But the energetic protons have ionized
the lower ionospheric layers to levels capable of absorbing most radio
signals that attempt to pass through that region. As a result, for large
regions of the Earth where radio paths traverse the high and polar latitudes,
a radio blackout is currently in effect.

Additional strong solar flare activity could significantly elevate
proton populations over and above what is currently being observed, during
the next two weeks. This could prove to be hazardous to the health of
spacecraft in orbit around the Earth. Indeed, it is possible for vulnerable
spacecraft to become crippled or even irrevocably lost. It is also possible
that spacecraft reliant upon solar arrays for power may observe permanent
degradations in performance. In other words, another effect of strong space
radiation is to permanently reduce the efficiency of solar panels, causing a
reduction in electrical output and therefore reduced lifetimes.

Space weather storms caused by the high velocity mass that is often
ejected from such powerful solar events can also significantly reduce the
lifetime of spacecraft through another method as well. During strong storms,
the outer reaches of the Earth's atmosphere heats up and bloats outward into
space. This bloating effect increases the atmospheric drag on spacecraft in
near-Earth orbits and can cause their orbital parameters to change rapidly.
Their lifetimes can therefore be reduced simply because the drag reduces
their altitude, which can result in early re-entry of the spacecraft back to
the Earth.

The intense radio bursts associated with these solar flares can produce
interference with antennas that happen to be directed toward the Sun during
the bursts. For example, if a strong solar flare occurs when the Sun is just
rising and a cellular phone or other radio communications network (wireless
internet, etc.) happens to be aligned in the direction of the rising Sun, the
intense radio emissions from the Sun may interfere with the communications
occurring in the network. This can result in poorer communications
performance.

Thus, there are many ways in which Region 10808 may influence our
activities here on the Earth during the next two weeks. Of course, this is
all dependent upon whether it is capable of retaining its volatile nature. At
the present time, this appears to be likely in the short-term. But such
strong activity also often results in some stabilization in the sunspot
complex, which could help curb future energetic activity.


** End of AstroAlert **

John F, better make sure you're well stocked-up on film...