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Composition of Titan's ionosphere
Luhmann, J. G.; Wahlund, J. -E.; Ip, W. -H. +13 more
We present Cassini Ion and Neutral Mass Spectrometer (INMS) measurements of ion densities on the nightside of Titan from April 16, 2005, and show that a substantial ionosphere exists on the nightside and that complex ion chemistry is operating there. The total ionospheric densities measured both by the INMS and the Cassini Radio and Plasma Wave (R…
Self-gravity wakes in Saturn's A ring measured by stellar occultations from Cassini
Sremčević, M.; Colwell, J. E.; Esposito, L. W.
An azimuthal brightness asymmetry in Saturn's A ring is caused by ephemeral agglomerations that continually form under the mutual gravity of the ring particles only to be torn apart by Keplerian shear. We calculate the shape and spacing of the self-gravity wakes from Cassini stellar occultations. The wakes are highly flatttened structures, with he…
Cassini observations of planetary-period magnetic field oscillations in Saturn's magnetosphere: Doppler shifts and phase motion
Dougherty, M. K.; Nichols, J. D.; Cowley, S. W. H. +5 more
Cassini magnetic field observations show that few-nT oscillations near the planetary rotation period, first observed in Pioneer-11 and Voyager-1 and -2 fly-by data, are essentially ubiquitous in Saturn's magnetosphere, though their character differs between the quasi-dipolar ring current region and the dawn tail. Examination of data from the ring-…
Cassini observations of flow-like features in western Tui Regio, Titan
Sotin, Christophe; Barnes, Jason W.; Rodriguez, Sebastien +9 more
A large (>3 × 104 km2), lobate, 5-µm-bright region seen by Cassini on Titan's leading equatorial region is best explained as a flow field. We discuss observations from the Visual and Infrared Mapping Spectrometer and Imaging Science Subsystem of the feature and present a map of the field. We establish relative ages o…
Ion cyclotron waves in Saturn's E ring: Initial Cassini observations
Russell, C. T.; Dougherty, M. K.; Leisner, J. S. +3 more
The magnetometer onboard the Cassini spacecraft observes ion cyclotron waves produced by both water-group (O+, OH+, H2O+, or H3O+) and O2+ ions at nearly all radial distances and local times within the E ring. These left-hand elliptically polarized waves travel…
Preliminary interpretation of Titan plasma interaction as observed by the Cassini Plasma Spectrometer: Comparisons with Voyager 1
Coates, A. J.; Crary, F.; Johnson, R. E. +15 more
The Cassini Plasma Spectrometer (CAPS) instrument observed the plasma environment at Titan during the Cassini orbiter's TA encounter on October 26, 2004. Titan was in Saturn's magnetosphere during the Voyager 1 flyby and also during the TA encounter. CAPS measurements from this encounter are compared with measurements made by the Voyager 1 Plasma …
A simple scale height model of the electron density in Saturn's plasma disk
Gurnett, D. A.; Persoon, A. M.; Kurth, W. S. +1 more
A study of electron densities in Saturn's inner magnetosphere is presented using measurements of the upper hybrid resonance frequency obtained from the Radio and Plasma Wave Science (RPWS) instrument on the Cassini spacecraft. The study uses data from the first 16 months of operation in orbit around Saturn. The distribution of density data spans l…
Electron temperature of Titan's sunlit ionosphere
Coates, A. J.; Wahlund, J. -E.; Galand, M. +2 more
Titan's upper atmosphere is ionized by solar radiation and particle bombardment from Saturn's magnetosphere. The induced ionosphere plays a key role in the coupling of Titan's atmosphere with the Kronian environment. It also provides unique signatures for identifying energy sources upon Titan's upper atmosphere. Here we focus on observations from …
Cassini observations of planetary-period oscillations of Saturn's magnetopause
André, N.; Lewis, G. R.; Coates, A. J. +8 more
Examination of Cassini magnetic field and plasma data in the outer boundary regions of Saturn's magnetosphere shows that magnetopause oscillations at the planetary period commonly occur, in phase with plasma pressure variations inside the magnetosphere. The peak-to-trough amplitude of the boundary oscillations mapped to the planet-Sun line is esti…
Cassini radio occultations of Saturn's ionosphere: Model comparisons using a constant water flux
Moore, Luke; Kliore, Arvydas J.; Mendillo, Michael +3 more
Recent radio occultations of Saturn's equatorial ionosphere by the Cassini spacecraft provide important insight into this poorly constrained region. Twelve new electron density profiles identify a clear dawn/dusk asymmetry as well as two apparently separate electron density peaks. This study uses a 3D general circulation model along with 1D water …