Cassini plasma spectrometer measurements of Jovian bow shock structure - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research Space Physics Année : 2003

Cassini plasma spectrometer measurements of Jovian bow shock structure

Résumé

The Cassini spacecraft on its way to Saturn flew by Jupiter and crossed its bow shock more than forty times on the dusk-side of the planet, whereas the early missions targeting Jupiter explored the dawnside. Here we report the first results concerning these bow shock crossings, based on the measurements of the Cassini Plasma Spectrometer (CAPS), the magnetometer, and the radio and plasma wave science (RPWS) instrument. We present data for five bow shock crossings, one at about 1920 local time (LT), the other four between 2100 and 2130 LT, 47.5°-50° beyond terminator. During the flyby the solar activity was high and variable. The measurements confirm that the Jovian bow shock is huge, extending over 700 RJ down the flank; Cassini was the first to observe such distant shock features. The bow shock was turbulent and very dynamic and magnetic fluctuations were superimposed on the shock; the downstream ion distributions exhibited bimodal structure time to time. For all bow shock crossings the onset of ion thermalization was a clear shock signature supported by an electrostatic wave signal; thermalization can be used as a signature of the shock location even in those cases when the field data are rather smeared. The strength of the shock potential weakened toward more distant regions even if the local Mach number did not decrease. Reflected protons were not detected upstream above our current sensitivity limit, but the incoming solar wind fluctuated in the foot region. We argue that the Jovian bow shock is not always in a steady state, and some of the observations might be connected with this fact.
Fichier principal
Vignette du fichier
Journal of Geophysical Research Space Physics - 2003 - Szego - Cassini plasma spectrometer measurements of Jovian bow.pdf (966.47 Ko) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-04110024 , version 1 (03-06-2023)

Licence

Copyright (Tous droits réservés)

Identifiants

Citer

Karoly Szego, David T. Young, Bruce Barraclough, Jean-Jacques Berthelier, Andrew J. Coates, et al.. Cassini plasma spectrometer measurements of Jovian bow shock structure. Journal of Geophysical Research Space Physics, 2003, 108 (A7), ⟨10.1029/2002JA009517⟩. ⟨hal-04110024⟩
34 Consultations
10 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More