The Radiation Belt Storm Probes that were launched on August 30, 2012, are nearing the completion of their 60-day commissioning period before beginning their prime mission. Nonetheless, interesting and useful data are being returned by the probes.
One of the instruments on these probes is the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS). This instrument is being managed by the University of Iowa Radio and Plasma Wave Group with Craig Kletzing being the principal investigator. The University of Iowa has a long history of involvement with the study of the magnetosphere, and was the home to Dr. James Van Allen who discovered the Van Allen Belts that RBSP is now probing.
EMFISIS monitors magnetic fields and plasma waves with three solenoids, oriented as if they were the 90-degree angles at the corner of a cube. Experiments in the past have only been able to monitor such waves in a single direction, but EMFISIS will measure E and H field components in all three directions as it also incorporates the electric field information gathered by the booms on the Electric Field and Wave Suite (EFW) instrument.
In essence, it’s a sophisticated Natural Radio receiver located within the radiation belts, far away from power-line interference and right near the source of the signals. These recordings are exceptionally clear for these reasons, plus the fact that the recordings are being made at 16-bit resolution, which was never done before within the radiation belts. Listen to the clarity of these first recordings! Here is a recording of chorus:
This is a whistler recorded from within the Van Allen Belts:
Both of these recordings are courtesy of NASA and the University of Iowa Radio and Plasma Wave Group. For more space sounds, you might want to check out Prof. Don Gurnett’s site at the University of Iowa: http://space-audio.org/
NASA’s RBSP was designed to help us understand the sun’s influence on Earth and near-Earth space by studying the Earth’s radiation belts on various scales of space and time.
The two RBSP spacecraft have nearly identical eccentric orbits and identical instrumentation. The orbits cover the entire radiation belt region and the two spacecraft lap each other several times over the course of the mission. With a spaced pair of satellites, RBSP can discriminate between spatial and temporal effects, and compare the effects of various proposed mechanisms for charged particle acceleration and loss.
Here are links to the mission pages for the RBSP: