How Earth Accelerates Electrons to 99.9 Percent of Light Speed : As the Sun's churning surface lets loose a belch of white-hot flame, it sends out a storm of radiation that washes over the solar system. Luckily for us, Earth's magnetic field shields us from most of these deadly rays. But overhead, something strange and lethal is happening when the solar wind bombards the Earth. A band of radioactive particles circling the planet, called the outer Van Allen belt, starts to charge up like a rail gun. It whips electrons along on its circular racetrack at a breakneck pace—near light speed. The powerful band ebbs and flows with solar radiation, but until today, nobody could be sure how it was creating such swift and energetic particles.
"This is like watching a natural particle accelerator in space," says Geoffrey Reeves, a magnetic field researcher at Los Alamos National Laboratory. Reeves and his team, with the help of a pair of newly launched NASA satellites called the Van Allen Probes, showed that the electrons in the belt gain their breathtaking velocity by hitching rides on radio waves. Daniel Baker, an astrophysicist with the study from the University of Colorado at Boulder, says that as solar radiation crushes against the Earth's magnetic field, a surge of radio and other waves begin to pump through the Van Allen belts. By chance, some of the radio waves are the exact frequency as electrons already twirling through the belt at slow speeds. "So the electrons hitch a ride—sort of surfing on these waves—and can be carried to these high speeds," Baker says. "It's a subtle but very powerful interaction."
Still, Jean-Luc Froeliger, the vice president of satellite engineering at Intelsat, which operates the world's largest commercial satellite fleet, cautions that while the Van Allen belts' high energy particles can do long-term damage to satellites, all modern satellites are built to withstand this particle barrage with extra shielding covering vital components, and major damage is rare. "I don't know any commercial satellite that has been totally destroyed by high energy electrons," Froeliger says, "but there is certainly an impact, in that the solar arrays degrade the more a satellite's bombarded by particles."
Article Link: http://www.popularmechanics.com/science/space/deep/how-earth-accelerates-electrons-to-99-percent-of-light-speed-15731824
NASA link on Van Allen Probes: http://science.nasa.gov/science-news/science-at-nasa/2013/28feb_thirdbelt/
Univ of Colarado link: http://www.colorado.edu/news/releases/2013/07/25/nasa-mission-involving-cu-boulder-discovers-particle-accelerator-heart-van
Journal Articles: http://www.rbsp-ect.lanl.gov/publications/Publications_Journals.php
Pic detail: Energy from the dynamic sun drives a complex chain of processes in the Earth's magnetosphere that ultimately lead to strong intensifications of the radiation belts. Geoff Reeves, Los Alamos National Laboratory
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