Heavy Ion Charge States in Jupiter's Polar Magnetosphere Inferred From Auroral Megavolt Electric Potentials

Clark, G.; Mauk, B. H.; Kollmann, P.; Paranicas, C.; Bagenal, F.; Allen, R. C.; Bingham, S.; Bolton, S. J.; Cohen, I. J.; Ebert, R. W.; Dunn, W. R.; Haggerty, D. K.; Houston, Stephen; Jackman, C. M.; Roussos, E.; Rymer, A. M.; Westlake, J. H.

doi:10.1029/2020ja028052

Cited by 23 publications

(27 citation statements)

References 60 publications

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“…For our model of energetic ion precipitation, we track doubly charged oxygen (O 2+ ) and triply charged sulfur (S 3+ ), as these charge states are consistent with the range of values in Clark et al (2016Clark et al ( , 2020. Using these charge states also facilitates comparison between our results and those of Cassidy et al (2013) and Breer et al (2019) for Europa, Liuzzo et al (2019b) for Callisto, and Poppe et al (2018) for Ganymede.…”

Section: Tablementioning

confidence: 86%

Influence of Europa’s Time‐Varying Electromagnetic Environment on Magnetospheric Ion Precipitation and Surface Weathering

et al. 2021

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The magnetic field of Jupiter (radius R J = 71,492 km) generates a magnetosphere that extends ∼50 R J at the sun-facing side and hundreds of R J at the sun-averted side (Joy et al., 2002). The magnetic dipole axis of Jupiter is inclined by 9.6° against its rotational axis, causing the magnetic field to "wobble" when viewed from a fixed point at the rotational equator. This wobble creates periodic variations in the magnetospheric field near Jupiter's Galilean satellites. Europa, the smallest of the Galilean satellites (radius R E = 1,560.8 km), orbits its parent planet at a distance of 9.38 R J , well within the magnetosphere. Europa possesses a dilute exosphere (e.g.,

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Section: Tablementioning

confidence: 86%

Influence of Europa’s Time‐Varying Electromagnetic Environment on Magnetospheric Ion Precipitation and Surface Weathering

et al. 2021

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“…Since TOF‐SSD instruments, like MMS/EIS and the Van Allen Probes/RBSPICE, have flown on many missions in the past, this correlation technique can most likely be applied to many other datasets during these types of flux enhancements across a wide range of plasma conditions or even other planetary magnetospheres. For instance, a similar approach has recently been applied to Juno/JEDI dataset to identify the dominant charge states of high energy heavy ions (oxygen and sulfur) in Jupiter's magnetosphere (Clark et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

Charge‐State‐Dependent Energization of Suprathermal Ions During Substorm Injections Observed by MMS in the Magnetotail

et al. 2020

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Understanding the energization processes and constituent composition of the plasma and energetic particles injected into the near-Earth region from the tail is an important component of understanding magnetospheric dynamics. In this study, we present multiple case studies of the high-energy (≳40 keV) suprathermal ion populations during energetic particle enhancement events observed by the Energetic Ion Spectrometer (EIS) on NASA's Magnetospheric Multiscale (MMS) mission in the magnetotail. We present results from correlation analysis of the flux response between different energy channels of different ion species (hydrogen, helium, and oxygen) for multiple cases. We demonstrate that this technique can be used to infer the dominant charge state of the heavy ions, despite the fact that charge is not directly measured by EIS. Using this technique, we find that the energization and dispersion of suprathermal ions during energetic particle enhancements concurrent with (or near) fast plasma flows are ordered by energy per charge state (E/q) throughout the magnetotail regions examined (~7 to 25 Earth radii). The ions with the highest energies (≳300 keV) are helium and oxygen of solar wind origin, which obtain their greater energization due to their higher charge states. Additionally, the case studies show that during these injections the flux ratio of enhancement is also well ordered by E/q. These results expand on previous results which showed that high-energy total ion measurements in the magnetosphere are dominated by high-charge-state heavy ions and that protons are often not the dominant species above~300 keV.

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“…Such high potentials were observed at Jupiter's poles by the Jupiter Energetic Particle Detector Instrument (JEDI) (Mauk et al., 2017) on‐board Juno. The MV potentials were associated with charge stripping of heavy iogenic ions required for SXR production (Clark et al., 2020). This combination of remote sensing data from the X‐ray telescopes and other wavebands with available in situ probe data are vital to enhance our understanding of the jovian X‐ray emissions.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Jupiter's X‐Ray Auroral Hot Spot Emissions Using Chandra

et al. 2021

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To help understand and determine the driver of jovian auroral X‐rays, we present the first statistical study to focus on the morphology and dynamics of the jovian northern hot spot (NHS) using Chandra data. The catalog we explore dates from December 18, 2000 up to and including September 8, 2019. Using a numerical criterion, we characterize the typical and extreme behavior of the concentrated NHS emissions across the catalog. The mean power of the NHS is found to be 1.91 GW with a maximum brightness of 2.02 Rayleighs (R), representing by far the brightest parts of the jovian X‐ray spectrum. We report a statistically significant region of emissions at the NHS center which is always present, the averaged hot spot nucleus (AHSNuc), with mean power of 0.57 GW and inferred average brightness of ∼1.2 R. We use a flux equivalence mapping model to link this distinct region of X‐ray output to a likely source location and find that the majority of mappable NHS photons emanate from the pre‐dusk to pre‐midnight sector, coincident with the dusk flank boundary. A smaller cluster maps to the noon magnetopause boundary, dominated by the AHSNuc, suggesting that there may be multiple drivers of X‐ray emissions. On application of timing analysis techniques (Rayleigh, Monte Carlo, Jackknife), we identify several instances of statistically significant quasi‐periodic oscillations (QPOs) in the NHS photons ranging from ∼2.3 to 36.4 min, suggesting possible links with ultra‐low frequency activity on the magnetopause boundary (e.g., dayside reconnection, Kelvin‐Helmholtz instabilities).

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Heavy Ion Charge States in Jupiter's Polar Magnetosphere Inferred From Auroral Megavolt Electric Potentials

Cited by 23 publications

References 60 publications

Influence of Europa’s Time‐Varying Electromagnetic Environment on Magnetospheric Ion Precipitation and Surface Weathering

Influence of Europa’s Time‐Varying Electromagnetic Environment on Magnetospheric Ion Precipitation and Surface Weathering

Charge‐State‐Dependent Energization of Suprathermal Ions During Substorm Injections Observed by MMS in the Magnetotail

Characteristics of Jupiter's X‐Ray Auroral Hot Spot Emissions Using Chandra

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