Search Publications
A rough-surface scattering function for Titan radar studies
Campbell, Bruce A.
Numerous studies show a relationship between radar backscattering and surface roughness. While estimating the statistical properties of small-scale topography is of particular interest for geologic analysis of Cassini radar data, there is no analytic description of radar scattering over a wide range of incidence angles and roughness. This paper pr…
Banana-polarized solitons in anisotropic plasmas related to Ulysses observations
Dubinin, E.; Sauer, K.; Baumgärtel, K. +1 more
Localized magnetic compressions associated with a rotation in the magnetic field direction have recently been reported after surveying Ulysses high-resolution data. Although the observed structures have similarities to usual Hall-MHD solitons, the banana-type polarization of the described rare events is a decisive signature which counts against su…
Possible eigenmode trapping in density enhancements in Saturn's inner magnetosphere
Gurnett, D. A.; Menietti, J. D.; Yoon, P. H.
We report a re-examination of observations of radio waves and banded fine structure observed by Cassini in the Saturn inner magnetosphere. These emissions have been identified in the past as Z-mode emission from possible density cavities along the inner edge of the Saturn plasma torus. A careful examination of the emission fine structure in a regi…
Plasma sheet fine structure at high latitude
Rème, H.; Kistler, L.; Lennartsson, O. W.
High-resolution ion observations made in recent years, by the TIMAS instrument on the Polar satellite and other instruments, reveal a dynamic and finely structured plasma sheet, at least at high latitude. This study invokes multipoint Cluster observations with the CIS CODIF instruments (ion composition and distribution function) to determine wheth…
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-…