The Juno Waves instrument detected a new broadband plasma wave emission (~50 Hz to 40 kHz) on 27 August 2016 as the spacecraft passed over the low-altitude polar regions of Jupiter. We investigated the characteristics of this emission and found similarities to whistler mode auroral hiss observed at Earth, including a funnel-shaped frequency-time feature. The electron cyclotron frequency is much higher than both the emission frequency and local plasma frequency, which is assumed to be ~20–40 kHz. The E/cB ratio was about three near the start of the event and then decreased to one for the rest of the period. A correlation of the electric field spectral density with the flux of an upgoing 20 to 800 keV electron beam was found, with a correlation coefficient of 0.59. We conclude that the emission is propagating in the whistler mode and is driven by the energetic upgoing electron beam.
Bibliographical noteFunding Information:
The authors would like to thank NASA and the various institutions that helped make the Juno mission possible. The research at the University of Iowa was supported by NASA through contract 699041X with Southwest Research Institute. The Juno data included herein will eventually be available from NASA's Planetary Data System. In the meantime, data may be requested from the lead author.
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- plasma waves
- whistler mode