Search Publications
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 …
Geologically recent tectonic, volcanic and fluvial activity on the eastern flank of the Olympus Mons volcano, Mars
Head, J. W.; Neukum, G.; van Gasselt, S. +4 more
We show evidence of very recent (<=25-40 Myr) geologic activity on the eastern flank of Olympus Mons volcano that includes a suite of fluvial (channel networks), volcanic (emplacement of lava flows and dikes), and tectonic (wrinkle ridges and troughs) processes. The combination and youth of these features confirms the importance of geological a…
Cluster PEACE observations of electron pressure tensor divergence in the magnetotail
Lucek, E.; Fazakerley, A. N.; Owen, C. J. +4 more
Cluster crossed the magnetotail neutral sheet on four occasions between 16:38 and 16:43 UT on 08/17/2003. The four-spacecraft capabilities of Cluster are used to determine spatial gradients from the magnetic field vectors and, for the first time, full electron pressure tensors. We find that the contribution to the electric field from the Hall term…
A global magnetic model of Saturn's magnetosphere and a comparison with Cassini SOI data
Alexeev, I. I.; Belenkaya, E. S.; Nichols, J. D. +4 more
A re-scaling of a recent model of Jupiter's magnetosphere incorporating ring current, magnetopause, and tail current systems is used as a starting-point for modeling Saturn's magnetospheric field. The model is compared with observations obtained by Cassini during its Saturn orbit insertion fly-through of Saturn's magnetosphere, and is shown to giv…
Electrostatic solitary structures observed at Saturn
Gurnett, D. A.; Dougherty, M. K.; Kurth, W. S. +2 more
We report observations of electric field solitary structures, measured by the Cassini Radio and Plasma Wave Science (RPWS) instrument in the vicinity of Saturn's magnetosphere with ambient magnetic fields that range from ~0.1 nT to 8000 nT. The peak-to-peak electric field amplitudes of the observed solitary structures range from a few µV/m t…
Europa's FUV auroral tail on Jupiter
Clarke, J. T.; Mauk, B. H.; Gérard, J. -C. +3 more
Ultraviolet images of Jupiter's northern aurora obtained in 2005 confirm the existence of an electromagnetic interaction between Europa and the Jovian ionosphere. The auroral signature shows a two-component structure: a quasi-circular Europa spot, followed by a previously undetected faint tail emission trailing in the direction of corotation flow.…
Kinetic properties of heavy solar wind ions from Ulysses-SWICS
Zurbuchen, T. H.; von Steiger, R.
The kinetic properties of heavy ions in the solar wind reflect the plasma processes governing the solar wind in the heliosphere. We use Ulysses-SWICS data that resolve heavy ions in a wide range of mass-per-charge values, 2 <= m/q <= 9.33, to investigate the heavy ions and their dynamic evolution throughout the heliosphere. While at 1 AU the…
A steep fan at Coprates Catena, Valles Marineris, Mars, as seen by HRSC data
Neukum, G.; Hauber, E.; Reiss, D. +4 more
We investigate a steep fan-like deposit in the Coprates Catena region, using the new High Resolution Stereo Camera (HRSC) data and other Martian data sets. Water flowing in a 45-km-long sapping valley entered a deep trough and formed a stepped fan 1100-m-high above the trough floor with a mean slope of 7.4°. The origin of the fan is uncertain. How…
Kinetic aspects of foreshock cavities
Schwartz, Steven J.; Meziane, Karim; Horbury, Timothy S. +2 more
We have investigated the kinetic signatures within, and at the edges of, a foreshock cavity. Such cavities are believed to be formed when an isolated collection of interplanetary magnetic field lines connect to quasi-parallel regions of the Earth's bow shock, allowing energetic ions to flow upstream and excavate a local cavity. Observations by the…
Formation of Saturn's ring spokes by lightning-induced electron beams
Krupp, N.; Woch, J.; Fränz, M. +10 more
Spokes are near-linear markings sometimes visible on Saturn's rings. They are widely accepted as being electrostatically-levitated sheets of ~0.6 micron-radius charged grains. Previously-suggested causes of the grains' charging do not agree with all spoke characteristics, which include their rapid generation, localized formation primarily in Satur…