Search Publications
Accelerated magnetosheath flows caused by IMF draping: Dependence on latitude
Farrugia, C. J.; Erkaev, N. V.; Torbert, R. B. +2 more
In previous work we used a semi-analytical treatment to describe accelerated magnetosheath flows caused by the draping of interplanetary magnetic field (IMF) lines around the magnetosphere. Here, we use the same approach, i.e., modeling the magnetic field lines as elastic strings, to examine how the magnetic tension force, one of the two agents re…
The observed composition of ions outflowing from Titan
Luhmann, J. G.; Mitchell, D. G.; Wahlund, J. -E. +8 more
We report on Cassini Ion and Neutral Mass Spectrometer (INMS) observations above Titan's exobase at altitudes of 2225 km to 3034 km. We observe significant densities of CH5+, HCNH+ and C2H5+ that require ion-molecule reactions to be produced in the quantities observed. The measured …
Spacecraft charging near Enceladus
Kempf, S.; Grün, E.; Hsu, H. -W. +1 more
In the vicinity of Enceladus, a geologically active moon of Saturn, the modeled spacecraft potential is significantly more negative than indicated by the Cassini Langmuir probe measurements. To understand this potential difference, we introduce two new dust-related charging currents: a) the dust ram current; and b) the dust impact-plasma current, …
First observation of the Venus UV dayglow at limb from SPICAV/VEX
Bertaux, Jean-Loup; Chaufray, Jean-Yves; Leblanc, Francois
We present the first limb observations of the dayglow emissions by the UV channel of SPICAV aboard Venus Express between October and December 2011. The CO Cameron bands between 180-260 nm and CO2+ doublet at 289 nm are clearly identified for the first time in the Venusian dayglow. The Cameron bands brightness peaks at 137.5 ±…
Spatial dependence of banded chorus intensity near the magnetic equator
Pickett, J. S.; Inan, U. S.; Bell, T. F. +1 more
Data from 12 different Cluster orbits containing banded chorus emissions, with observations from 22 different events spread across the four Cluster spacecraft, are used to show the spatial dependence of banded chorus intensity near the magnetic equator under conditions of moderate magnetic disturbance (Kp ≤ 5). The intensities for upper…
Consequences of negative ions for Titan's plasma interaction
Brecht, Stephen H.; Ledvina, Stephen A.
A hybrid particle code has been used to examine how Titan's interaction with Saturn's magnetosphere is affected by the presence of negative ions in Titan's ionosphere. The simulations self-consistently include a version of Titan's ionosphere represented by 8 generic positive ion species, over 40 ion-neutral chemical reactions, ion-neutral collisio…
Magnetospheric line radiation event observed simultaneously on board Cluster 1, Cluster 2 and DEMETER spacecraft
Pickett, J. S.; Santolík, O.; Parrot, M. +1 more
We present a case study of a magnetospheric line radiation (MLR) event observed simultaneously by Cluster 1 and Cluster 2 during a perigee passage at a radial distance of about 4 RE and, at the same time, by the low-orbiting DEMETER satellite. This unique constellation enables us to analyze spatiotemporal variability of the phenomenon. …
Cassini capturing of freshly-produced water-group ions in the Enceladus torus
Yaroshenko, V. V.; Miloch, W. J.; Thomas, H. M. +1 more
The water vapor plume on the geological-active south-polar region of the moon Enceladus is recognized as the main source of Saturn's neutral torus centered on the Enceladus orbit. The composition of the torus is dominated by water group species. Recent in situ Cassini plasma spectrometer measurements indicate the existence of freshly produced, slo…
Equatorially confined warm trapped ions at around 100 eV near the plasmapause
Yamauchi, M.; Dandouras, I.; Rème, H. +1 more
Near the equatorial plasmapause at around 4-5 Earth radius (RE) geocentric distance, pancake distributed tens of eV ions are sometimes found, as previously reported by Olsen et al. (1987). Cluster CIS data during perigee traversals in 2001-2002 (nearly 200 traversals) revealed new features of these equatorially-trapped warm ions. (1) Th…
Wind-induced atmospheric escape: Titan
Johnson, R. E.; Hartle, R. E.; Simpson, D. G. +2 more
Rapid thermospheric flows can significantly enhance the atmospheric loss rates and structures of atmospheric coronae of planetary bodies. Using descriptions of atmospheric escape based on molecular kinetic models, we show that such flows at the exobase of Titan could significantly increase the calculated constituent thermal and nonthermal escape r…