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Ultra-fast electrons explain third radiation ring around Earth
23 September 2013
In the already complicated science of what creates - and causes constant change in - two giant doughnuts of radiation surrounding Earth, researchers have added a new piece of information: some of the electrons reach such enormous energies that they are driven by an entirely different set of physical processes. These results were published in a paper in Nature Physics on 22 September 2013.
Understanding the nature of these radiation belts and how they swell and shrink over time is an integral part of interpreting, and perhaps someday predicting, the space weather that surrounds our planet. Such space weather can, among other things, cause complications in electronics systems aboard satellites we depend on for communications and GPS.
The discovery of the radiation belts was the first discovery of the space age, observed in 1958 by the Explorer I spacecraft. Scientists soon realised that the belts can change shape in concert with incoming disturbances from the sun, sometimes quite dramatically. In February 2013, researchers announced observations from NASA's Van Allen Probes, showing a previously undetected configuration. The belts showed a distinct unusually narrow ring beyond the inner belt persisting for a month in September 2012 while additional particles funnelled in to create a third, larger, outermost belt. This previously unknown configuration of three bands, changed what was previously understood about the belts and set people in search of new explanations.