| Title: |
Preliminary results on Saturn's inner plasmasphere as observed by Cassini: Comparison with Voyager |
| Authors: |
E. C. Sittler, Jr.; Thomsen, M.; Chornay, D.; D. Shappirio, M.; Simpson, D.; E. Johnson, R.; T. Smith, H.; J. Coates, A.; M. Rymer, A.; Crary, F.; J. Mccomas, D.; T. Young, D.; Reisenfeld, D.; Dougherty, M.; André, N.; E. P. Connerney, J.; D. Richardson, J. |
| Contributors: |
Centre d'étude spatiale des rayonnements (CESR); Université Toulouse III - Paul Sabatier (UT3); Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) |
| Source: |
ISSN: 0094-8276. |
| Publisher Information: |
CCSD; American Geophysical Union |
| Publication Year: |
2005 |
| Collection: |
Université Toulouse III - Paul Sabatier: HAL-UPS |
| Subject Terms: |
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]; [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] |
| Description: |
We present an analysis of Saturn's inner plasmasphere as observed by the Cassini Plasma Spectrometer (CAPS) experiment during Cassini's initial entry into Saturn's magnetosphere when the spacecraft was inserted into orbit around Saturn. The ion fluxes are divided into two subgroups: protons and water group ions. We present the relative amounts of these two groups and the first estimates of their fluid parameters: ion density, flow velocity and temperature. We also compare this data with electron plasma measurements. Within the plasmasphere and inside of Enceladus' orbit, water group ions are about a factor of $10 greater than protons in number with number densities exceeding 40 cm À3. Within this inner region the spacecraft acquires a negative potential so that the electron density is underestimated. The electron and proton temperatures, which could not be measured in this region by Voyager, are T $ 2 eV at L $ 3. Also, within this inner region the protons, because of a negative spacecraft potential, appear to be super-corotating. By enforcing the condition that protons and water group ions are co-moving we may be able to acquire an independent estimate of the spacecraft potential relative to that estimated when comparing ionelectron measurements. Using our estimates of plasma properties, we estimate the importance of the rotating plasma on the stress balance equation for the inner magnetosphere and corresponding portion of the ring current. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1029/2005GL022653 |
| Availability: |
https://hal.science/hal-00013182; https://hal.science/hal-00013182v1/document; https://hal.science/hal-00013182v1/file/2005GL022653.pdf; https://doi.org/10.1029/2005GL022653 |
| Rights: |
info:eu-repo/semantics/OpenAccess |
| Accession Number: |
edsbas.29B2E63E |
| Database: |
BASE |