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At approximately 0855 UTC on August 1, 2010, a C3.2 magnitude soft X-ray
flare erupted from NOAA Active Sunspot Region 11092 (1092).
At nearly the same time, a massive filament eruption occurred. Prior to
the filament's eruption, NASA's Solar Dynamics Observatory (SDO)
Atmospheric Imaging Assembly (AIA) instruments revealed an enormous plasma
filament stretching across the sun's northern hemisphere. When the solar
shock wave triggered by the C3.2-class X-ray explosion plowed through this
filament, it appears to have caused the filament to erupt, sending out a
huge plasma cloud (a coronal mass ejection, or CME).
A shock wave can be seen emerging from the origin of the X-ray flare and
sweeping across the sun's northern hemisphere into the filament field. The
impact of this shock wave may well have propelled the filament into space.
The movies (see links, below) seem to support the conclusion that both
eruptions, occurring together, are linked, despite the approximately
400,000 kilometer distance between the flare and the filament eruption.
How can this be? While we cannot always see the magnetic field lines
between solar features (magnetic field lines are not visible unless there
is plasma trapped along these field lines), we can assume from this event
that huge connecting field lines existed between the sunspot region and
the filament in the sun's northern hemisphere.
This is an amazing event. A complex series of eruptions involving most of
the visible surface of the sun has occurred, ejecting plasma toward the
Earth. This coronal mass ejection (CME) rides the solar wind. Depending on
the speed of the solar wind and the ejected plasma, this cloud will reach
Earth's magnetosphere sometime between August 3 and August 5.
High-latitude sky watchers should be alert for auroras. Radio
communications by way of the ionosphere may become degraded soon after the
CME arrives, and the degraded conditions may last for up to three days.
First view at the 304-Angstrom wavelength by SDO/AIA:
<http://www.youtube.com/watch?v=VyaqxKkSCpU>
Second view at the 171-Angstrom wavelength by SDO/AIA:
<http://www.youtube.com/watch?v=HW_-yQY6YlA>
Source: SDO/AIA
--
73 de NW7US, Tomas David Hood ( http://tomas-david-hood.com )
Contributing editor, Propagation Columns:
CQ Magazine, CQ VHF, Popular Communications
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