Still images and
MPEG movie of an
active aurora observed during the major geomagnetic
storm of July 15-16, 2000
(see the caption below the figures for details)
The six images above show the northern aurora at various stages in its development as it was observed with the Far Ultraviolet (FUV) Imaging System during a major geomagnetic storm that occurred on July 15-16. The images were obtained when the spacecraft was near apogee (7.2 Earth radii) and was looking down onto the northern polar region. The Sun is to the lower right. The storm, which peaked between 2200 UT on July 15 and 0200 UT on July 16 with a Dst index as low as -295 nT (according to the World Data Center in Kyoto), was classified by NOAA's Space Environment Center as a G5 or "extreme" storm. The July 15-16 storm was triggered by a fast coronal mass ejection (CME) that hit the Earth's magnetosphere around 14:40 UT on Saturday, July 15. The CME erupted from the Sun on Friday, July 14, and and was associated with a powerful solar flare. The CME traveled toward Earth at a speed of three million miles per hour, according to the Space Environment Center. The auroral emissions observed with the FUV/WIC are from molecular nitrogen that is excited by precipitating electrons.
MPEG movie of the July 15 aurora (1.5 Mb)
Photo and movie credit:S. Mende and H. Frey, Space Sciences Laboratory, University of California, Berkeley; Randy Gladstone, Southwest Research Institute