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- Title
Forward Modeling of 3-D Ion Properties in Jupiter's Magnetosphere Using Juno/JADE-I Data.
- Authors
Jian-zhao Wang; Bagenal, Fran; Wilson, Robert J.; Nerney, Edward; Crary, Frank; Dols, Vincent; Ebert, Rob W.; Valek, Phil W.; Allegrini, Frederic; Kim, Thomas K.; Szalay, Jamey R.
- 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.
- Subjects
UNITED States. National Aeronautics &; Space Administration; MAGNETOSPHERE; JUPITER (Planet); HEAVY ions; ION migration &; velocity; FLOW velocity; COHEN'S kappa coefficient (Statistics)
- Publication
Journal of Geophysical Research. Space Physics, 2024, Vol 129, Issue 4, p1
- ISSN
2169-9380
- Publication type
Article
- DOI
10.1029/2023JA032218