While the chorus has been audible even before the Space Age — ham radio operators could sometimes hear it in decades past — the clarity of these measurements is "really quite striking," Kletzing said.
Initial findings show the outer radiation belt to be much more dynamic and rapidly changing than anticipated, said the University of Colorado's Daniel Baker, principal investigator for the electron proton telescope on each probe.
The Van Allen probes — formerly known as the Radiation Belt Storm Probes — were launched from Cape Canaveral on Aug. 30. They were named after the late University of Iowa astrophysicist James Van Allen, who discovered the radiation belts that bear his name a half-century ago.
Recording of waves: http://tinyurl.com/b2az6ex