Tuesday, August 03, 2010

Propagation Alert: Will it hit Earth?

On August 1, 2010, the Solar Dynamics Observatory (SDO) observed a beautiful prominence eruption that may hit Earth and cause a geomagnetic storm. As the solar cycle progresses and the Sun becomes more active there will be many more opportunities to observe the causes of space weather. Want to see what happens? Follow the event at spaceweather.com.

And from the Spaceweather website:

On August 1st, the entire Earth-facing side of the sun erupted in a tumult of activity. There was a C3-class solar flare, a solar tsunami, multiple filaments of magnetism lifting off the stellar surface, large-scale shaking of the solar corona, radio bursts, a coronal mass ejection and more.

High-latitude sky watchers should be alert for auroras tonight. One and possibly two coronal mass ejections (CMEs) are heading toward Earth, propelled by the solar eruptions of August 1st (see below). NOAA forecasters estimate a 10% chance of major geomagnetic storms and a 45% chance of at least some geomagnetic activity when the clouds arrive on August 3rd and 4th.

And finally this report from our good friend Tomas Hood

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:

Second view at the 171-Angstrom wavelength by SDO/AIA:

Source: SDO/AIA

73 de NW7US, Tomas David Hood ( http://tomas-david-hood.com/ )


Main NW7US Page: http://hfradio.org/
Twitter Space WX : @hfradiospacewx
Twitter NW7US : @NW7US

Podcast: http://podcast.hfradio.org/ (restarting Summer 2010)

Linux User #32405 - Since 1996