Search Publications
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…
Motion of observed structures calculated from multi-point magnetic field measurements: Application to Cluster
Balogh, A.; Zong, Q. -G.; Lucek, E. +5 more
A new method is described which calculates the velocity of observed, quasi-stationary structures at every moment in time from multi-point magnetic field measurements. Once the magnetic gradient tensor G = $\nabla$$\vec {B and the time variation of the magnetic field have been estimated at every moment, the velocity can then be determined, in princ…
Modification of the dichotomy boundary on Mars by Amazonian mid-latitude regional glaciation
Head, James W.; Neukum, Gerhard; Marchant, David R. +1 more
Restoration of the dichotomy boundary to its original position to assess its origin requires a thorough knowledge of processes responsible for its degradation and retreat. The unique fretted terrain, located along the Deuteronilus-Protonilus Mensae northern mid-latitude portion of the boundary, has been long held to provide clues to dichotomy degr…
Structure of the separatrix region close to a magnetic reconnection X-line: Cluster observations
Pickett, J. S.; André, M.; Khotyaintsev, Y. +9 more
We use Cluster spacecraft observations to study in detail the structure of a magnetic reconnection separatrix region on the magnetospheric side of the magnetopause about 50 ion inertial lengths away from the X-line. The separatrix region is the region between the magnetic separatrix and the reconnection jet. It is several ion inertial lengths wide…
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…