Kim, TK;
Ebert, RW;
Valek, PW;
Allegrini, F;
McComas, DJ;
Bagenal, F;
Chae, K;
... Nicolaou, G; + view all
(2019)
Method to Derive Ion Properties from Juno JADE Including Abundance Estimates for O⁺ and S²⁺.
Journal of Geophysical Research: Space Physics
, 125
(2)
, Article e2018JA026169. 10.1029/2018ja026169.
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Abstract
The Jovian Auroral Distributions Experiment Ion sensor (JADE‐I) on Juno is a plasma instrument that measures the energy‐per‐charge (E/Q) distribution of 0.01 to 46.2 keV/q ions over a mass‐per‐charge (M/Q) range of 1 – 64 amu/q. However, distinguishing O+ and S2+ from JADE‐I's measurements is a challenging task due to similarities in their M/Q (≈ 16 amu/q). Because of this, O+ and S2+ have not been fully resolved in the in‐situ measurements made by plasma instruments at Jupiter (e.g., Voyager PLS and Galileo PLS) and their relative ratios has been studied using physical chemistry models and UV remote observations. To resolve this ambiguity, a ray‐tracing simulation combined with carbon foil effects is developed and used to obtain instrument response functions for H+, O+, O2+, O3+, Na+, S+, S2+, and S3+. The simulation results indicate that JADE‐I can resolve the $M/Q$ ambiguity between O+ and S2+ due to a significant difference in their charge state modification process and a presence of a large electric potential difference (≈ 8 kV) between its carbon foils and MCPs. A forward model based on instrument response functions and eight convected kappa distributions is then used to obtain ion properties at the equatorial plasma sheet (≈ 36 jovian radii) in the pre‐dawn sector of magnetosphere. The number density ratio between O+ and S2+ for the selected plasma sheet crossings ranges from 0.2 to 0.7 (mean value 0.37 ± 0.12) and the number density ratio between total oxygen ions to total sulfur ions ranges from 0.2 to 0.6 (0.41 ±0.09).
| Type: | Article |
|---|---|
| Title: | Method to Derive Ion Properties from Juno JADE Including Abundance Estimates for O⁺ and S²⁺ |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2018ja026169 |
| Publisher version: | https://doi.org/10.1029/2018JA026169 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10079332 |
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