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Cassini-Plasma Interaction Simulations Revealing the Cassini Ion Wake Characteristics : Implications for In-Situ Data Analyses and Ion Temperature Estimates

Authors :
Lina Hadid
G. Déprez
Mika Holmberg
T. Nilsson
R. J. Wilson
S. Hess
Hans Huybrighs
Fabrice Cipriani
Michiko Morooka
M. Felici
Laboratoire de Physique des Plasmas (LPP)
Observatoire de Paris
Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Source :
Journal of Geophysical Research Space Physics, Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2021, 126 (8), ⟨10.1029/2020JA029026⟩
Publication Year :
2021
Publisher :
Uppsala universitet, Institutet för rymdfysik, Uppsalaavdelningen, 2021.

Abstract

We have used Spacecraft Plasma Interaction Software (SPIS) simulations to study the characteristics (i.e., dimensions, ion depletion, and evolution with the changing spacecraft attitude) of the Cassini ion wake. We focus on two regions, the plasma disk at 4.5-€“4.7 RS, where the most prominent wake structure will be formed, and at 7.6 RS, close to the maximum distance at which a wake structure can be detected in the Cassini Langmuir probe (LP) data. This study also reveals how the ion wake and the spacecraft plasma interaction have impacted the Cassini LP measurements in the studied environments, for example, with a strong decrease in the measured ion density but with minor interference from the photoelectrons and secondary electrons originating from the spacecraft. The simulated ion densities and spacecraft potentials are in very good agreement with the LP measurements. This shows that SPIS is an excellent tool to use for analyses of LP data, when spacecraft material properties and environmental parameters are known and used correctly. The simulation results are also used to put constraints on the ion temperature estimates in the inner magnetosphere of Saturn. The best agreement between the simulated and measured ion density is obtained using an ion temperature of 8 eV at ∼4.6 RS. This study also shows that SPIS simulations can be used in order to better constrain plasma parameters in regions where accurate measurements are not available.

Details

Language :
English
ISSN :
21699380 and 21699402
Database :
OpenAIRE
Journal :
Journal of Geophysical Research Space Physics, Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2021, 126 (8), ⟨10.1029/2020JA029026⟩
Accession number :
edsair.doi.dedup.....0d59df3c61ba5081ebb55b5a7e8be972