The High‐Latitude Extension of Jupiter's Io Torus: Electron Densities Measured by Juno Waves

Elliott, Sadie; Sulaiman, A. H.; Kurth, W. S.; Faden, J.; Allegrini, F.; Valek, P. W.; Connerney, J. E. P.; Ebert, R. W.; Szalay, J. R.; Bagenal, F.; Bolton, S. J.

doi:10.1029/2021ja029195

Cited by 14 publications

(23 citation statements)

References 73 publications

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“…Our second criterion ensures that this does not happen. show the total electron density derived by Waves (Elliott et al, 2021). There is very good agreement between the partial electron density from Jovian Auroral Distributions Experiment-E and the total electron density from Waves.…”

Section: Density and Temperaturementioning

confidence: 52%

“…The dark blue “+” symbols are at 1‐s time resolution of the JADE instrument, and the lighter blue curves are 30‐s averages. Panel (d) also shows the total electron density derived by Waves in violet and dark red (from Elliott et al., 2021).…”

Section: Observationsmentioning

confidence: 99%

“…(d and e) partial electron density (50 eV to 100 keV) and temperature as derived by numerical integration at 1s resolution (blue “+”) and 30 s averages (lightblue curve). The violet and dark red symbols in panel (d) show the total electron density derived by Waves (Elliott et al., 2021). There is very good agreement between the partial electron density from Jovian Auroral Distributions Experiment‐E and the total electron density from Waves.…”

Section: Observationsmentioning

confidence: 99%

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Electron Partial Density and Temperature Over Jupiter's Main Auroral Emission Using Juno Observations

et al. 2021

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We present a survey of electron partial densities (i.e., the portion of the total density measured between ∼0.05 and 100 keV) and temperatures in Jupiter's main auroral emission region using plasma measurements from the Jovian Auroral Distributions Experiment (JADE) on Juno. The electron partial density increases from ∼0.01 or 0.1 cm−3 near the main oval to a few cm−3 at the edge of the measurable part of the UV emission equatorward of the main oval. The electron temperature is highest near the main oval at ∼10–20 keV and decreases equatorward down to ∼0.3–2 keV. The JADE electron partial density agrees within a factor of ∼2 with the total electron densities derived from Juno‐Waves when the comparison is possible. The electron density and temperature trends are consistent for all sampled longitudes, for the north and the south, and there is no significant trend with radial distance in the range examined in this study (1.25–1.96 RJ). The electron density is anti‐correlated with the temperature and the characteristic energy. The ratio of the magnetic field strength to the electron density is maximum near the main oval.

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Section: Density and Temperaturementioning

confidence: 52%

Section: Observationsmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

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Electron Partial Density and Temperature Over Jupiter's Main Auroral Emission Using Juno Observations

et al. 2021

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“…For example, Waves data give access to the electron densities e E n at Juno's position (Tetrick et al, 2017) from inspection of the high-frequency cut-off of the auroral hiss emission, which is a function of the electron plasma frequency   pe E f . Thus, the Waves data can provide a complementary information to JADE measurements, which can also provide electron densities over the polar regions: see Sulaiman et al (2021) for the method and Elliott et al (2021). A more detailed description of this method is given in Appendix A-3 in the Supporting Information S1.…”

Section: Description Of Our Methods To Retrieve the Key Parameters Fr...mentioning

confidence: 99%

A Preliminary Study of Magnetosphere‐Ionosphere‐Thermosphere Coupling at Jupiter: Juno Multi‐Instrument Measurements and Modeling Tools

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The dynamics of the Jovian magnetosphere are controlled by the interplay of the planet's fast rotation, its main iogenic plasma source and its interaction with the solar wind. Magnetosphere‐Ionosphere‐Thermosphere (MIT) coupling processes controlling this interplay are significantly different from their Earth and Saturn counterparts. At the ionospheric level, they can be characterized by a set of key parameters: ionospheric conductances, electric currents and fields, exchanges of particles along field lines, Joule heating and particle energy deposition. From these parameters, one can determine (a) how magnetospheric currents close into the ionosphere, and (b) the net deposition/extraction of energy into/out of the upper atmosphere associated to MIT coupling. We present a new method combining Juno multi‐instrument data (MAG, JADE, JEDI, UVS, JIRAM and Waves) and modeling tools to estimate these key parameters along Juno's trajectories. We first apply this method to two southern hemisphere main auroral oval crossings to illustrate how the coupling parameters are derived. We then present a preliminary statistical analysis of the morphology and amplitudes of these key parameters for eight among the first nine southern perijoves. We aim to extend our method to more Juno orbits to progressively build a comprehensive view of Jovian MIT coupling at the level of the main auroral oval.

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“…From the latter, we can calculate f z from Equation 7 above and this is over plotted in Figure 7 showing a reasonable agreement with the lower cutoff of the emission, supporting the identification as Z-mode. Analysis methods identifying plasma wave modes in the Jovian environment characterized by the condition f c /f p » 1 have been systematically discussed by Sulaiman et al (2021) and also discussed by Elliott et al (2021).…”

Section: Z-mode Surveymentioning

confidence: 99%

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

et al. 2021

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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.

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The High‐Latitude Extension of Jupiter's Io Torus: Electron Densities Measured by Juno Waves

Cited by 14 publications

References 73 publications

Electron Partial Density and Temperature Over Jupiter's Main Auroral Emission Using Juno Observations

Electron Partial Density and Temperature Over Jupiter's Main Auroral Emission Using Juno Observations

A Preliminary Study of Magnetosphere‐Ionosphere‐Thermosphere Coupling at Jupiter: Juno Multi‐Instrument Measurements and Modeling Tools

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

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