Another look at the X-2 Solar Flare
CHANCE OF STORMS: Friday the 13th could be a lucky day for sky watchers. Several minor CMEs propelled toward Earth earlier this week by active sunspot AR2297 are expected to arrive en masse on March 12th and 13th. Their collective impact could spark bright auroras around the Arctic Circle. NOAA forecasters estimate a 60% chance of G1-class geomagnetic storms when the CMEs arrive. Aurora alerts: text, voice
X2-FLARE AND RADIO BLACKOUT: All week long, sunspot AR2297 has been crackling with solar flares. Yesterday it produced a really big one. On March 11th at 16:22 UT (09:22 PDT), Earth orbiting-satellites detected an X2-class flare. The blast zone was larger than Earth itself:
Extreme ultraviolet radiation from the explosion ionized the upper layers of Earth's atmosphere, causing HF radio blackouts and other propagation effects on the dayside of our planet, particularly over the Americas: map.
In New Mexico, amateur radio astronomer Thomas Ashcraft was observing the sun using a wideband spectrograph when the flare occured. The radio blackout was obvious at every frequency from 15 MHz to 26 MHz:
"The X-flare scrambled the ionosphere thoroughly so that no decametric radio signals were supported in my part of the world," says Ashcraft. "The ionosphere started to reform after about fifteen minutes when stations began to reappear. (The stuff visible during the blackout was my own observatory electricity. Nothing exterior.)"
A coronal mass ejection (CME) was propelled into space by the explosion. However, we do not yet know if it will hit Earth. A glancing blow is possible on March 13th or 14th. Confirmation awaits the belated arrival of coronagraph data from SOHO. Stay tuned. Solar flare alerts: text, voice
Realtime Space Weather Photo Gallery
WHY DO SOLAR FLARES EXPLODE?: Later today, March 12th, NASA will launch a fleet of spacecraft to investigate the mystery of magnetic reconnection: On the sun, magnetic field lines cross, cancel, reconnect and—bang! A solar flare explodes. How does the simple act of crisscrossing magnetic fields trigger such a ferocious blast? The Magnetospheric Multiscale Mission aims to find out. Get the full story from Science@NASA. http://www.spaceweather.com/
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