Search Publications
Altitude of Saturn's aurora and its implications for the characteristic energy of precipitated electrons
Bonfond, B.; Clarke, J. T.; Gérard, J. -C. +4 more
Images of Saturn's aurora at the limb have been collected with the Advanced Camera for Surveys on board the Hubble Space Telescope. They show that the peak of Saturn's nightside emission is generally located 900-1300 km above the 1-bar level. On the other hand, methane and H2 columns overlying the aurora have been determined from the an…
Ionospheric storms on Mars: Impact of the corotating interaction region
Barabash, S.; Lundin, R.; Woch, J. +5 more
Measurements made by the ASPERA-3 and MARSIS experiments on Mars Express have shown, for the first time, that space weather effects related to the impact of a dense and high pressure solar wind (corotating interaction region) on Mars cause strong perturbations in the martian induced magnetosphere and ionosphere. The magnetic barrier formed by pile…
A north-south difference in the rotation rate of auroral hiss at Saturn: Comparison to Saturn's kilometric radio emission
Gurnett, D. A.; Persoon, A. M.; Hospodarsky, G. B. +3 more
Broadband whistler-mode emissions, commonly observed by the Cassini spacecraft at high latitudes in Saturn's magnetosphere at frequencies below about 100 Hz, have characteristics very similar to auroral hiss observed at high latitudes in Earth's magnetosphere. In contrast to terrestrial auroral hiss, which shows no obvious rotational modulation, S…
Smoothness of Titan's Ontario Lacus: Constraints from Cassini RADAR specular reflection data
Lorenz, R. D.; Wye, L. C.; Zebker, H. A.
Cassini RADAR altimetry data collected on the 49th flyby of Titan (2008 December 21) over Ontario Lacus in Titan's south polar region provides strong evidence for an extremely smooth surface, with less than 3 mm rms surface height variation over the 100m-wide Fresnel zone. Histograms of the raw radar echoes imply a mirror-like specular reflection …
Cassini detection of Enceladus' cold water-group plume ionosphere
Coates, A. J.; Thomsen, M. F.; Wilson, R. J. +6 more
This study reports direct detection by the Cassini plasma spectrometer of freshly-produced water-group ions (O+, OH+, H2O+, H3O+) and heavier water dimer ions (HxO2)+ very close to Enceladus where the plasma begins to emerge from the plume. The data …
Amazonian-aged fluvial valley systems in a climatic microenvironment on Mars: Melting of ice deposits on the interior of Lyot Crater
Head, J. W.; Dickson, J. L.; Fassett, C. I.
Valley networks, regional drainage patterns suggesting liquid water stability at the surface, are confined to early in the history of Mars (the Noachian/Hesperian boundary and before), prior to a major climate transition to the hyperarid cold conditions of the Amazonian. Several later fluvial valley systems have been documented in specific Hesperi…
Detecting nanoparticles at radio frequencies: Jovian dust stream impacts on Cassini/RPWS
Gurnett, D. A.; Kaiser, M. L.; Meyer-Vernet, N. +1 more
We analyse wave observations by the Cassini/RPWS instrument performed during the Jovian fly-by, when the on-board dust analyser recorded dust streams which were interpreted as nanoparticles moving at about the solar wind speed. The observed wave pulses are produced by ionisation of dust grains impacting the spacecraft. Nanoparticles are detected b…
Source regions of banded chorus
Pickett, J. S.; Inan, U. S.; Bell, T. F. +1 more
ELF/VLF chorus emissions are very intense electromagnetic plasma waves that are naturally and spontaneously excited near the magnetic equatorial plane outside the plasmasphere during periods of magnetic disturbance. These emissions are believed to play an important role in the acceleration of 10 to 100 keV radiation belt electrons to MeV energies …
Cassini RADAR images at Hotei Arcus and western Xanadu, Titan: Evidence for geologically recent cryovolcanic activity
Lorenz, R. D.; Janssen, M. A.; Lunine, J. I. +14 more
Images obtained by the Cassini Titan Radar Mapper (RADAR) reveal lobate, flowlike features in the Hotei Arcus region that embay and cover surrounding terrains and channels. We conclude that they are cryovolcanic lava flows younger than surrounding terrain, although we cannot reject the sedimentary alternative. Their appearance is grossly similar t…
Periodicity in Saturn's magnetosphere: Plasma cam
Young, D. T.; Burch, J. L.; DeJong, A. D. +1 more
Plasma ion data from the Cassini Plasma Spectrometer (CAPS) are examined for all orbits from October 25, 2004 through Dec. 26, 2007. To eliminate effects of incomplete angular coverage, data are only used from the CAPS anode that is closest to viewing into the corotational flow and within 20° of that flow. The data are plotted in the SKR-based SLS…