Cassini plasma spectrometer measurements of Jovian bow shock structure

K. Szegö, David T. Young, Bruce Barraclough, Jean Jacques Berthelier, Andrew J. Coates, David J. McComas, Frank J. Crary, Michele K. Dougherty, G. Erdős, Donald A. Gurnett, William S. Kurth, Michelle F. Thomsen

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

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.

Original languageEnglish
Article number1287
JournalJournal of Geophysical Research: Space Physics
Volume108
Issue numberA7
DOIs
Publication statusPublished - 2003

Fingerprint

bows
spectrometers
Spectrometers
spectrometer
shock
Ions
Plasmas
Plasma waves
plasma
Solar wind
Radio waves
Magnetometers
Planets
Jupiter
ions
Mach number
Spacecraft
Protons
Electrostatics
radio

Keywords

  • Bow shock
  • Cassini
  • Fields and particles
  • Jupiter
  • Solar wind parameters

ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science

Cite this

Szegö, K., Young, D. T., Barraclough, B., Berthelier, J. J., Coates, A. J., McComas, D. J., ... Thomsen, M. F. (2003). Cassini plasma spectrometer measurements of Jovian bow shock structure. Journal of Geophysical Research: Space Physics, 108(A7), [1287]. https://doi.org/10.1029/2002JA009517

Cassini plasma spectrometer measurements of Jovian bow shock structure. / Szegö, K.; Young, David T.; Barraclough, Bruce; Berthelier, Jean Jacques; Coates, Andrew J.; McComas, David J.; Crary, Frank J.; Dougherty, Michele K.; Erdős, G.; Gurnett, Donald A.; Kurth, William S.; Thomsen, Michelle F.

In: Journal of Geophysical Research: Space Physics, Vol. 108, No. A7, 1287, 2003.

Research output: Contribution to journalArticle

Szegö, K, Young, DT, Barraclough, B, Berthelier, JJ, Coates, AJ, McComas, DJ, Crary, FJ, Dougherty, MK, Erdős, G, Gurnett, DA, Kurth, WS & Thomsen, MF 2003, 'Cassini plasma spectrometer measurements of Jovian bow shock structure', Journal of Geophysical Research: Space Physics, vol. 108, no. A7, 1287. https://doi.org/10.1029/2002JA009517
Szegö, K. ; Young, David T. ; Barraclough, Bruce ; Berthelier, Jean Jacques ; Coates, Andrew J. ; McComas, David J. ; Crary, Frank J. ; Dougherty, Michele K. ; Erdős, G. ; Gurnett, Donald A. ; Kurth, William S. ; Thomsen, Michelle F. / Cassini plasma spectrometer measurements of Jovian bow shock structure. In: Journal of Geophysical Research: Space Physics. 2003 ; Vol. 108, No. A7.
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