SDO

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The Solar Dynamics Observatory (SDO) is a NASA science mission that was launched into space in February 2010 to provide uninterrupted observations of the Sun at high spatial and temporal resolution. The broad range of research topics enabled by SDO aims to provide a deeper understanding of how the variability of our nearest star affects life on Earth. This research is achieved by investigating how the Sun’s magnetic field is generated and structured, and how this stored magnetic energy is converted and released into the heliosphere and geospace in the form of solar wind, energetic particles, and variations in solar irradiance.

The data shown here comprise images from the Atmospheric Imaging Assembly (AIA) instrument on board SDO, which provides 4096x4096-pixel images of the solar corona at a rapid cadence. Each image was taken using one of several narrow-band filters, most of which transmit wavelengths located in the extreme ultraviolet (EUV) part of the electromagnetic spectrum. Due to the thermal structure of the solar corona, light emitted at these particular wavelengths is indicative of the presence of matter at specific temperatures. Names of AIA channels, such as "171", "193", "211", "304", and "1600" channels shown here, correspond to the approximate wavelength of light [in Angstroms] transmitted by the respective narrow-band filters.

Some of the most prominent features in AIA data, in particular the 171, 193, and 211 channels, are coronal loops - typically showing up as bright, arch-like structures. These structures are believed to be parallel to magnetic field lines permeating the corona. Loops that contain matter heated to a particular temperature are visible in the various AIA channels: the 171, 193, and 211 channels show matter that has been heated to 1 MK, 1.5 MK, and 2MK respectively. Evolution of the coronal magnetic field is evident in an apparent adjustment of the coronal loops; some loops appear to brighten as others fade. Usually such adjustments occur smoothly and steadily, but at other times the reconfiguration of the coronal magnetic field is achieved by violent eruptions that cause bright flares accompanied with matter being ejected into space.

Other features include filaments, the dark, mostly linear structures that often extend over long distances across the solar disk. Movies of AIA data show that, after days of remaining largely intact, filaments can suddenly destabilize, as the cool, dark matter of the filament is observed to be accelerated upward away from the Sun. Some of this matter leaves the Sun's gravitational field and enters interplanetary space, and the rest is observed to stream back down toward the visible surface. Why and how such filaments destabilize and erupt is a subject of active research.

Watch a filament eruption. (Best viewed in the 304 Å wavelength band).

Watch coronal loops. (Best viewed in the 304 or 171 Å wavelength bands).

Images captured over a 24-hour period on December 6, 2010. Individual frames in this video were captured 24 seconds apart, and are displayed here at 25 frames per second, for a timelapse speedup of 600x.

Imagery courtesy of NASA/SDO and the AIA science team at the Lockheed Martin Solar and Astrophysics Laboratory.

Thanks to Michael Sims from NASA Ames, Estelle Dodson from Lockheed Martin, Marc DeRosa, Neil Hurlburt, and Ralph Seguin from LMSAL, and Todd Hoeksema from Stanford Solar Observatories Group for their generous assistance creating and documenting this feature.