spacetoday.net: Atmosphere acts as heat shield for solar storms

Posted: Fri, May 10, 2002, 8:58 AM ET (1258 GMT)
Magnetosphere illustration (NASA)

New data from a NASA spacecraft confirm that a region of the Earth's upper atmosphere acts as a heat shield, absorbing energy from solar storms, but in the process generating a cloud of plasma that surrounds the planet. Observations by the Imager for Magnetopause to Aurora Global Exploration (IMAGE) spacecraft show that the upper ionosphere, a region of the atmosphere 300 to 1,000 km above the Earth's surface, absorbs energy from a multimillion-amp electric current generated when energetic particles from solar storms interact with the Earth's magnetosphere. This turns a portion of the gas — a few hundred tons for a typical storm — into a plasma that is distributed around the planet by the magnetosphere. This plasma can disrupt satellites and interfere with GPS signals.