Analysis of Whistler-Mode and Z-Mode Emission in the Juno Primary Mission

J. D. Menietti, T. F. Averkamp, W. S. Kurth, M. Imai, J. B. Faden, G. B. Hospodarsky, O. Santolik, G. Clark, F. Allegrini, S. S. Elliott, A. H. Sulaiman, S. J. Bolton

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6 Scopus citations


At the end of the Juno primary mission, we report observations of whistler mode chorus and Z-mode emission. The Juno orbits are evolving and much better coverage of the whistler mode chorus source region has resulted since the earlier surveys. Bursty chorus emission extending to ∼30° latitude and to frequencies less than the lower hybrid frequency near the source region imply high electron energies (>100 keV). Average chorus intensity levels peak at ∼10−3 nT2 near M-shell of 8–9 and magnetic latitude of ∼5°. Z-mode emission is identified at higher latitudes generally near and inward of the Io torus with intensity levels as much as two orders of magnitude higher than Z-mode emissions observed at Saturn. Inferred source regions for the Z-mode are consistent with the inner edge of the Io torus and with auroral field lines that may also support Jovian kilometric and decametric emission. Parametric fitting functions are evaluated for both whistler mode chorus and Z-mode, describing wave intensity as a function of frequency, magnetic latitude, and M-shell. Both whistler mode and Z-mode waves may have significant impact on electron scattering and acceleration at Jupiter as recent models indicate.

Original languageEnglish (US)
Article numbere2021JA029885
JournalJournal of Geophysical Research: Space Physics
Issue number11
StatePublished - Nov 2021

Bibliographical note

Funding Information:
The authors wish to thank K. Kurth for clerical assistance and J. Chrisinger for help with the figures, and P. Kollmann for providing JEDI pitch angle data. JDM acknowledges support from NASA grant 80NSSC19K1262. Research conducted at the University of Iowa was supported by NASA New Frontiers Program through Contract 699041X with Southwest Research Institute. The work of MI was supported by the JSPS KAKENHI Grant Number JP20K22371. G. Clark and F. Allegrini were funded by NASA New Frontiers Program for Juno (for G. Clark this was through a subcontract with Southwest Research Institute). OS acknowledges support from the LTAUSA17070 Inter‐Excellence Project.

Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.


  • Juno
  • Jupiter
  • magnetospheric physics
  • whistler mode emissions


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