Researchers from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) team at the University of Iowa have released a new recording of an intriguing and well-known phenomenon known as “chorus,” made on Sept. 5, 2012. The Waves tri-axial search coil magnetometer and receiver of EMFISIS captured several notable peak radio wave events in the magnetosphere that surrounds the Earth. The radio waves, which are at frequencies that are audible to the human ear, are emitted by the energetic particles in the Earth’s magnetosphere.

“People have known about chorus for decades,” says EMFISIS principal investigator Craig Kletzing, of the University of Iowa. “Radio receivers are used to pick it up, and it sounds a lot like birds chirping. It was often more easily picked up in the mornings, which along with the chirping sound is why it’s sometimes referred to as ‘dawn chorus.’”
via NASA

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