From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Sep 09 2005 - 12:57:22 UTC
>From: Cary Oler <oler_at_solar.spacew.com>
>To: sun-earth_at_SkyandTelescope.com
>Subject: AstroAlert: Intense Solar Flaring Continues - 9 September
>Date: Fri, 9 Sep 2005 05:16:49 +0000 (GMT)
>
>=================================================================
>This Is SKY & TELESCOPE's AstroAlert for Sun-Earth Interactions
>=================================================================
>
>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 **
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