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December 5: 2012-Aug-31 filament eruption observed by AIA and SWAP

  December 5: 2012-Aug-31 Filament Eruption  
  2012-Aug-31 filament eruption observed by AIA and SWAP  


Click on the above image for a movie of the event



Because SWAP has a relatively large field of view, its observations can be combined with observations from other images, like AIA on SDO, to get a larger-scale picture of coronal dynamics. This movie, which shows a dramatic filament eruption that occurred in August 2012, brings together SWAP's observations with a channel of AIA that shows plasma at a similar temperature. The bright features in the movie are hot, close to one million degrees, while the dark structures are cool and dense, with temperatures closer to the roughly 10,000 degrees of the solar chromosphere. Instead of emitting light like the bright structures, we see them in silhouette, blocking light from structures below them.

This eruption was an excellent example of the ways in which the dynamics of the corona are frequently controlled by twisted magnetic fields, part of structures solar physicists call "flux ropes". The visible filament, the most prominent dark structure involved in the eruption, lies along one strand of magnetic field tangled in a large, coil of magnetic fields that compose this flux rope. When this structure becomes unstable, which can happen for any number of reasons, it expands and untiwsts, and, as different parts of its structure become active, we can see more and more coiled threads brighten as the result of heating. Some of these bright threads erupt along with the flux rope, but others remain behind, kinking and expanding in different ways.

Before the eruption, these twisted magnetic fields store huge amounts of potential energy. As the eruption unfolds, the process of magnetic reconnection allows some of these magnetic fields to dissipate their energy, which is converted into heat and kinetic energy, the energy of motion. Most of the kinetic energy is directed into the structures that erupt from the sun, passing through the SWAP field-of-view on their way to become a full-fledged coronal mass ejection. The heat can drive the plasma involved in the eruption to huge temperatures, tens of millions of degrees. As newly formed magnetic structures cool to about one million degrees from these high temperatures, they appear in SWAP and AIA images as bright loops, which you can see towards the end of the movie.