Van Allen Probes EMFISIS Waves
Chorus from 2013-01-26

The Van Allen Probes EMFISIS Waves instruments detected these signals with three orthogonal magnetic antennas (Bu, Bv, Bw) during UTC hour 09 of January 26, 2013, in conjunction with the BARREL (Balloon Array for Radiation belt Relativistic Electron Losses) campaign. Featured is another collection of the now-familiar chorus emission, but showing significant diversity with falling tones and short falling "hooks" preceding the more typical rising tones.

Chorus waves in Earth's magnetosphere are generated in the Van Allen radiation belts by electrons spiraling along Earth's magnetic field lines in this region. Once generated, the chorus waves interact with the moving electrons, either accelerating them to higher energies or disturbing the spiral orbit of the electrons and causing them to fall into Earth's upper atmosphere along the magnetic field lines.

The animation shows a frequency-time spectrogram of the data with a moving cursor that indicates the time position of the audio track.