Charge states of energetic ions in Jupiter's radiation belt inferred from absorption microsignatures of Io

Selesnick, R. S.; Cohen, C. M. S.

doi:10.1029/2008ja013722

Cited by 15 publications

(30 citation statements)

References 24 publications

(30 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We propose that ion-neutral interactions are playing a role in redistributing the energetic (>hundreds of keV) heavy ion charge states near the trans-Europa cloud and inward. This idea reconciles the observational differences that show the charge states of energetic oxygen are primarily O + at large distances (this work and Allen et al, 2019), a more even mixture of O + and O ++ is found near the neutral cloud (Clark, Mauk, et al, 2016), and a maximum charge state value of O 8+ is found near Io (Selesnick & Cohen, 2009). 5.…”

Section: Discussionsupporting

confidence: 90%

“…We propose that ion‐neutral interactions are playing a role in redistributing the energetic (>hundreds of keV) heavy ion charge states near the trans‐Europa cloud and inward. This idea reconciles the observational differences that show the charge states of energetic oxygen are primarily O + at large distances (this work and Allen et al, 2019), a more even mixture of O + and O ++ is found near the neutral cloud (Clark, Mauk, et al, 2016), and a maximum charge state value of O 8+ is found near Io (Selesnick & Cohen, 2009). The recent overview from Mauk et al (2020) showing that megavolt potentials span most of the polar cap area (see our Figure 1, magenta curves) and the analysis of the associated heavy ions in this paper, we believe this supports the hypothesis of soft X‐ray emissions that are sourced by precipitating energetic heavy ions.…”

Section: Discussionsupporting

confidence: 89%

“…However, the results appear to differ slightly from the analysis of Galileo Energetic Particle Detector data which hinted that oxygen was more evenly distributed between O + and O ++ . Even though the previous studies are all consistent with charge states being similar for <MeV energies, that seems to change when comparing the results to those of Selesnick and Cohen (2009), which showed that very energetic heavy ions (≥5 MeV/nucleon) were dominantly fully stripped (or nearly fully) near Io. We present two ideas that may account for these differences in the literature: (1) The low-energy (<tens of keV) ions are the source of the particles falling through the megavolt electric potentials and therefore these measurements best reflect the plasma distributions and (2) ion-neutral interactions are playing a role in redistributing the heavy ion charge states in Jupiter's inner-to-middle magnetosphere.…”

Section: 1029/2020ja028052mentioning

confidence: 78%

See 2 more Smart Citations

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

et al. 2020

View full text Add to dashboard Cite

In this paper, we exploit the charge-dependent nature of auroral phenomena in Jupiter's polar cap region to infer the charge states of energetic oxygen and sulfur. To date, there are very limited and sparse measurements of the >50 keV oxygen and sulfur charge states, yet many studies have demonstrated their importance in understanding the details of various physical processes, such as X-ray aurora, ion-neutral interactions in Jupiter's neutral cloud, and particle acceleration theories. In this contribution, we develop a technique to determine the most abundant charge states associated with heavy ions in Jupiter's polar magnetosphere. We find that O + and S ++ are the most abundant and therefore iogenic in origin. The results are important because they provide (1) strong evidence that soft X-ray sources are likely due to charge stripping of magnetospheric ions and (2) a more complete spatial map of the oxygen and sulfur charge states, which is important for understanding how the charge-and mass-dependent physical processes sculpt the energetic particles throughout the Jovian magnetosphere.

show abstract

Section: Discussionsupporting

confidence: 90%

Section: Discussionsupporting

confidence: 89%

Section: 1029/2020ja028052mentioning

confidence: 78%

See 1 more Smart Citation

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

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Nénon and André (2019) demonstrated that energetic ion charge states likely evolve with energy and distance from Jupiter. Selesnick and Cohen (2009) suggest that at the highest energies, heavy ions may be fully ionized.…”

Section: Particle Tracing Model Gentoomentioning

confidence: 99%

Energetic Ion Dynamics in the Perturbed Electromagnetic Fields Near Europa

et al. 2019

View full text Add to dashboard Cite

We model the dynamics of energetic magnetospheric ions in the perturbed electromagnetic fields near Jupiter's moon Europa. The inhomogeneities in the fields near Europa are generated by the induced dipole field from the moon's subsurface ocean as well as the Alfvénic plasma interaction with its ionosphere and induced field. Inhomogeneities in Europa's ionosphere at various length scales generate substantial asymmetries in the mass loading process that further complicate the structure of the moon's electromagnetic environment. In our study, the electromagnetic fields near Europa are obtained from an established hybrid model, whereas a particle tracing tool is applied to analyze the precipitation of the three most abundant energetic ion species (hydrogen, oxygen, and sulfur) onto the moon's surface at various energies from 1 keV up to 5 MeV. To isolate the contributions of the induced dipole and ionospheric mass loading to the field perturbations and the resulting precipitation patterns, we consider multiple field configurations of successively increasing complexity. For ion energies in the kiloelectron volt regime, magnetic field line draping effectively shields large portions of Europa's surface against energetic ion impacts and drastically alters the shape of the precipitation patterns, compared to uniform fields. The fine structure of these patterns strongly depends on the complexity of the applied ionosphere model. Only in the megaelectron volt regime, the precipitation patterns are qualitatively similar for uniform and draped fields. However, the precipitation of megaelectron volt ions onto Europa is still not homogeneous, since the strong magnetospheric field keeps ion gyroradii much smaller than the moon's radius.

show abstract

“…The jovian plasma and energetic charged particle environment is composed of an admixture of hydrogen, sulfur, and oxygen ions (e.g., Krupp et al, 2004; Mauk et al, 2004; Thomas et al, 2004). Associated heavy ion charge states are predominately O + and S ++ ; however, studies have shown that this may vary with energy and/or distance from Jupiter (e.g., Allen et al, 2019; Clark et al, 2016; Selesnick & Cohen, 2009).…”

Section: Introductionmentioning

confidence: 99%

Juno Observations of Heavy Ion Energization During Transient Dipolarizations in Jupiter Magnetotail

et al. 2020

View full text Add to dashboard Cite

Transient magnetic reconnection and associated fast plasma flows led by dipolarization fronts play a crucial role in energetic particle acceleration in planetary magnetospheres. Despite large statistical observations on this phenomenon in the Earth's magnetotail, many important characteristics (e.g., mass or charge dependence of acceleration efficiency and acceleration scaling with the spatial scale of the system) of transient reconnection cannot be fully investigated with the limited parameter range of the Earth's magnetotail. The much larger Jovian magnetodisk, filled by a mixture of various heavy ions and protons, provides a unique opportunity for such investigations. In this study, we use recent Juno observations in Jupiter's magnetosphere to examine the properties of reconnection associated dipolarization fronts and charged particle acceleration. High-energy fluxes of sulfur, oxygen, and hydrogen ions show clear mass-dependent acceleration with energy ∼ m 1/3 . We compare Juno observations with similar observations in the Earth's magnetotail and discuss possible mechanism for the observed ion acceleration.

show abstract

Charge states of energetic ions in Jupiter's radiation belt inferred from absorption microsignatures of Io

Cited by 15 publications

References 24 publications

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

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

Energetic Ion Dynamics in the Perturbed Electromagnetic Fields Near Europa

Juno Observations of Heavy Ion Energization During Transient Dipolarizations in Jupiter Magnetotail

Contact Info

Product

Resources

About