Jovian chorus is generated in Jupiter's radiation belts by electrons spiraling along Jupiter's magnetic field lines in this region. Once generated, the chorus waves interact with the moving electrons, disturbing the spiral orbit of the electrons and causing them to fall into the Jupiter's ionosphere along the magnetic field lines at high latitudes.
Chorus waves consist of a rapid succession of intense ascending tones, rising in frequency over very short time intervals, each tone lasting typically less than one second. The frequencies of these rising tones occur in the audio frequency range and sound like a dawn chorus of chirping birds, a sound which gives these waves their name.
These signals were recorded by the Voyager 1 plasma wave instrument during the flyby of Jupiter on March 5, 1979. Low frequency noise has been filtered out and the recorded signals have been slowed down by a factor of 4 in order to shift the frequency down to make the chorus signals easier to hear. The labels on the spectrogram provide the actual values of time along the horizontal axis and frequency along the vertical axis. The intensity is color-coded with weak signals blue and strong signals red.
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The Radio and Plasma Wave Group, Department of Physics & Astronomy, College of Liberal Arts & Sciences.