Dynamics of Saturn's magnetosphere from MIMI during Cassini's orbital insertion

Authors

S. M. Kmigis, Johns Hopkins University Applied Physics Laboratory
D. G. Mitchell, Johns Hopkins University Applied Physics Laboratory
D. C. Hamilton, College of Computer, Mathematical, & Natural Sciences
N. Krupp, Max Planck Institute for Solar System Research
S. Livi, Johns Hopkins University Applied Physics Laboratory
E. C. Roelof, Johns Hopkins University Applied Physics Laboratory
J. Dandouras, Institut de Recherche en Astrophysique et Planétologie (IRAP)
T. P. Armstrong, Fundamental Technologies LLC
B. H. Mauk, Johns Hopkins University Applied Physics Laboratory
C. Paranicas, Johns Hopkins University Applied Physics Laboratory
P. C. Brandt, Johns Hopkins University Applied Physics Laboratory
S. Bolton, Jet Propulsion Laboratory
A. F. Cheng, Johns Hopkins University Applied Physics Laboratory
T. Choo, Johns Hopkins University Applied Physics Laboratory
G. Gloeckler, College of Computer, Mathematical, & Natural Sciences
J. Hayes, Johns Hopkins University Applied Physics Laboratory
K. C. Hsieh, College of Science
W. H. Ip, National Central University
S. Jaskulek, Johns Hopkins University Applied Physics Laboratory
E. P. Keath, Johns Hopkins University Applied Physics Laboratory
E. Kirsch, Max Planck Institute for Solar System Research

Document Type

Article

Publication Date

2-25-2005

Abstract

The Magnetospheric Imaging Instrument (MIMI) onboard the Cassini spacecraft observed the saturnian magnetosphere from January 2004 until Saturn orbit insertion (SOI) on 1 July 2004. The MIMI sensors observed frequent energetic particle activity in interplanetary space for several months before SOI. When the imaging sensor was switched to its energetic neutral atom (ENA) operating mode on 20 February 2004, at ∼10 ³ times Saturn's radius R S (0.43 astronomical units), a weak but persistent signal was observed from the magnetosphere. About 10 days before SOI, the magnetosphere exhibited a day-night asymmetry that varied with an ∼11-hour periodicity. Once Cassini entered the magnetosphere, in situ measurements showed high concentrations of H ⁺, H 2 ⁺, O ⁺, OH ⁺, and H 2O ⁺ and low concentrations of N ⁺. The radial dependence of ion intensity profiles implies neutral gas densities sufficient to produce high loss rates of trapped ions from the middle and inner magnetosphere. ENA imaging has revealed a radiation belt that resides inward of the D ring and is probably the result of double charge exchange between the main radiation belt and the upper layers of Saturn's exosphere.

Identifier

20044385740 (Scopus)

Publication Title

Science

External Full Text Location

https://doi.org/10.1126/science.1105978

ISSN

00368075

PubMed ID

15731445

First Page

1270

Last Page

1273

Issue

5713

Volume

307

Recommended Citation

Kmigis, S. M.; Mitchell, D. G.; Hamilton, D. C.; Krupp, N.; Livi, S.; Roelof, E. C.; Dandouras, J.; Armstrong, T. P.; Mauk, B. H.; Paranicas, C.; Brandt, P. C.; Bolton, S.; Cheng, A. F.; Choo, T.; Gloeckler, G.; Hayes, J.; Hsieh, K. C.; Ip, W. H.; Jaskulek, S.; Keath, E. P.; and Kirsch, E., "Dynamics of Saturn's magnetosphere from MIMI during Cassini's orbital insertion" (2005). Faculty Publications. 19776.
https://digitalcommons.njit.edu/fac_pubs/19776