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Comparisons between MHD model calculations and observations of Cassini flybys of Titan
Dougherty, Michele K.; Hansen, Kenneth C.; Sokolov, Igor V. +6 more
The Cassini spacecraft passed by Titan on 26 October 2004 (Ta flyby) and 13 December 2004 (Tb flyby). In both cases the Cassini Orbiter entered Titan's ionosphere and flew through Titan's dynamic wake region. In this paper, we present our simulation results of these two flybys using our three-dimensional multispecies MHD model. This model is a sli…
Titan's near magnetotail from magnetic field and electron plasma observations and modeling: Cassini flybys TA, TB, and T3
André, N.; Lewis, G. R.; Russell, C. T. +14 more
The first close Titan encounters TA, TB, and T3 of the Cassini mission at almost the same Saturnian local time ∼1030 and in the same spatial region downstream of Titan have enabled us to study the formation of the tail of its induced magnetosphere. The study is based on magnetic field and electron plasma observations as well as three-dimensional m…
Enceladus: A significant plasma source for Saturn's magnetosphere
Hill, T. W.; Pontius, D. H.
The Cassini Plasma Spectrometer has reported dramatic perturbations of the magnetospheric plasma flow in a region extending at least 30 satellite radii away from Saturn's small but active icy satellite Enceladus. We interpret these observations here by means of a steady state model of the electrodynamic coupling between Enceladus and Saturn. Neutr…
First results from the ionospheric radio occultations of Saturn by the Cassini spacecraft
Anabtawi, Aseel; Barbinis, Elias; Fleischman, Don +9 more
The first set of near-equatorial occultations of the Saturn ionosphere was obtained by the Cassini spacecraft between May and September of 2005. The occultations occurred at near-equatorial latitudes, between 10°N and 10°S, at solar zenith angles from about 84° to 96°. The entry observations correspond to dusk conditions and the exit ones to dawn.…
Waves and horizontal structures in Titan's thermosphere
Waite, J. H.; Yelle, R. V.; Müller-Wodarg, I. C. F. +1 more
The Ion Neutral Mass Spectrometer (INMS) on board the Cassini spacecraft carried out in situ measurements of neutral gas composition above 1025 km altitude in Titan's atmosphere during its flybys in October 2004 (TA) and April 2005 (T5). Strong perturbations are present in the N2 and CH4 densities which we interpret as vertic…
Nature of magnetic fluctuations in Saturn's middle magnetosphere
Russell, C. T.; Dougherty, M. K.; Leisner, J. S. +2 more
The saturnian magnetosphere contains a rich array of plasma wave and MHD wave phenomena. These waves are fed by mass loading in the region of the E ring starting with Enceladus at 3.9 Saturn radii (Rs). In this paper we examine the nature of these waves in what we term to be the middle magnetosphere from just outside the mass loading at Enceladus …
Orientation, location, and velocity of Saturn's bow shock: Initial results from the Cassini spacecraft
Russell, C. T.; Dougherty, M. K.; Tsurutani, B. T. +8 more
The Cassini spacecraft commenced its tour of the planet Saturn on 1 July 2004 (GMT). During the insertion orbit, the Cassini magnetometer (MAG), radio/plasma wave experiment (RPWS), and plasma spectrometer (CAPS) obtained in situ measurements of the magnetic field and plasma conditions associated with Saturn's environment. Analysis of the magnetic…
Saturn's auroral morphology and activity during quiet magnetospheric conditions
Coates, A. J.; Dougherty, M. K.; Kurth, W. S. +8 more
We report the results of a coordinated Hubble Space Telescope-Cassini campaign that took place between 26 October and 2 November 2005. During this period, Saturn's magnetosphere was in an expanded state and the solar wind was quiet, as indicated by the location of the magnetopause, in situ particle measurements, weak auroral SKR emission, and the …
Energetic nitrogen ions within the inner magnetosphere of Saturn
Johnson, R. E.; Paranicas, C.; Sittler, E. C. +9 more
We investigate the importance of nitrogen ions within Saturn's magnetosphere and their contribution to the energetic charged particle population within Saturn's inner magnetosphere. This study is based on the Voyager observations of Saturn's magnetosphere and Cassini observations. The latter have shown that water group ions dominate both the plasm…
Whistler-mode auroral hiss emissions observed near Saturn's B ring
Gurnett, D. A.; Hospodarsky, G. B.; Kurth, W. S. +2 more
An unusual whistler-mode emission, similar to terrestrial auroral hiss, was observed by the radio and plasma wave instrument on the Cassini spacecraft during the 1 July 2004 pass over the rings of Saturn. By using an electron density model that is consistent with measurements of the local electron plasma frequency, ray-tracing calculations have be…