Forward Modeling of 3-D Ion Properties in Jupiter’s Magnetosphere Using Juno/JADE-I Data

Jian zhao Wang, Fran Bagenal, Robert J. Wilson, Edward Nerney, Frank Crary, Vincent Dols, Rob W. Ebert, Phil W. Valek, Frederic Allegrini, Thomas K. Kim, Jamey R. Szalay

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The Jovian Auroral Distributions Experiment Ion sensor (JADE-I) on NASA’s Juno mission provides in-situ measurements of ions from 0.1 to 46.2 keV/q inside Jupiter’s magnetosphere. JADE-I is used to study the plasma with two types of datasets from the same measurement: Time-of-flight (TOF) and SPECIES. The TOF dataset provides mass-per-charge measurements with a range of 1–64 amu/q but oversamples particles over 6π steradian viewing per spacecraft spin and has little directional information. On the other hand, the SPECIES dataset can provide a good measurement of the flow direction but does not provide mass-per-charge information due to the telemetry limit. In this study, we developed a 2-step forward modeling method that combines the advantages and avoids the disadvantages of TOF and SPECIES data to derive the 3-D properties of heavy ions. Assuming that the ion velocity distribution can be described with the kappa distribution, we first perform the forward model fit of the TOF data to calculate the relative abundance of heavy ion species. Then we fix the relative abundance and perform the second forward model fit on the SPECIES data. Using this method, we obtain the densities of different heavy ions, the shared temperature and kappa value, and the 3-D flow velocity vector. Some data examples of the equatorial plasma disk before Perijove 24 are included to demonstrate the method. Plasma properties can then be mapped to explore spatial and temporal variabilities in Jupiter’s magnetosphere.

Original languageEnglish (US)
Article numbere2023JA032218
JournalJournal of Geophysical Research: Space Physics
Volume129
Issue number4
DOIs
StatePublished - Apr 2024

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Space and Planetary Science

Keywords

  • forward modeling
  • Jupiter
  • magnetosphere
  • plasma disk

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