STEREO - Solar Terrestrial Relations Observatory
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Performing with a Flare


On March 25, 2008 STEREO observed its first M-class (medium-sized) solar flare, which was also associated with a coronal mass ejection. Flares are intense, though short-lived, solar storms. Interestingly, three active regions were lined up across the center of the Sun, but the one on the far left produced the flare and CME. A careful look at the middle region reveals a burst of activity just before the flare blasts from the area to its left. The magnetic field orientations of these active regions still belong to the old solar cycle: sunspots of the new cycle will show reversed magnetic orientation. The video clip shows about 14 hours of activity.

Radio Emissions


Energetic electrons accelerated by flares and CMEs generate radio emissions that can be detected remotely and can be used to track disturbances moving out from the Sun, as seen here with the STEREO waves instrument). The March 25 event started with a powerful flare, which produced electrons moving at 25% the speed of light. Some of these flare electrons crashed into the solar surface producing light across a broad range of the different kinds of light*, including X-rays and ultraviolet radiation. Others shoot out into interplanetary space, where they generated radio emissions at successively lower frequencies, corresponding to locations successively further from the sun. The CME moved out from the sun at much slower speeds, producing much slower drifting bursts

Last Revised: March 19, 2018 15:00:39 UTC
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