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Survey of ion plasma parameters in Saturn's magnetosphere
Thomsen, M. F.; Tokar, R. L.; Reisenfeld, D. B. +6 more
A survey of the bulk plasma ion properties observed by the Cassini Plasma Spectrometer instrument over roughly the first 4.5 years of its mission in orbit around Saturn is presented. The moments (density, temperature, and flow velocity) of the plasma distributions below 50 keV have been computed by numerical integration of the observed counts in t…
A new form of Saturn's magnetopause using a dynamic pressure balance model, based on in situ, multi-instrument Cassini measurements
Coates, A. J.; Krupp, N.; Dougherty, M. K. +9 more
The shape and location of a planetary magnetopause can be determined by balancing the solar wind dynamic pressure with the magnetic and thermal pressures found inside the boundary. Previous studies have found the kronian magnetosphere to show rigidity (like that of Earth) as well as compressibility (like that of Jupiter) in terms of its dynamics. …
Enceladus plume variability and the neutral gas densities in Saturn's magnetosphere
Johnson, R. E.; Mitchell, D. G.; Smith, H. T. +3 more
Neutral particle dominance over charged particles in Saturn's magnetosphere was evident prior to Cassini's arrival at Saturn in 2004. The observation of active plumes emanating from the south pole of Enceladus suggests that this small moon is likely to be the principal source of neutrals in Saturn's magnetosphere. Cassini has flown through the plu…
Cassini observations of a Kelvin-Helmholtz vortex in Saturn's outer magnetosphere
Coates, A. J.; Krupp, N.; Dougherty, M. K. +9 more
We present Cassini observations of a plasma vortex in Saturn's dayside outer magnetosphere. The vortex encounter took place on 13 December 2004 as Cassini was travelling toward the planet. The spacecraft crossed the magnetopause 3 times, before being immersed in the low-latitude boundary layer. During the transition between the boundary layer and …
Magnetospheric period oscillations at Saturn: Comparison of equatorial and high-latitude magnetic field periods with north and south Saturn kilometric radiation periods
Coates, A. J.; Dougherty, M. K.; Lamy, L. +4 more
It has recently been shown using Cassini radio data that Saturn kilometric radiation (SKR) emissions from the Northern and Southern hemispheres of Saturn are modulated at distinctly different periods, ∼10.6 h in the north and ∼10.8 h in the south, during the southern summer conditions that prevailed during the interval from 2004 to near-equinox in…
Magnetic field oscillations near the planetary period in Saturn's equatorial magnetosphere: Variation of amplitude and phase with radial distance and local time
Dougherty, M. K.; Andrews, D. J.; Cowley, S. W. H. +1 more
We present an analysis of the ∼11 h oscillations in Saturn's near-equatorial magnetic field, using Cassini data acquired during 2004-2007. We assume the oscillation period is given by the magnetic phase model derived by Provan et al. (2009) over the same interval, and use this to combine the data to determine the variation of the oscillation ampli…
Detection and measurement of ice grains and gas distribution in the Enceladus plume by Cassini's Ion Neutral Mass Spectrometer
Waite, J. H.; Teolis, B. D.; Magee, B. A. +2 more
We report on the measurements of the Cassini Ion Neutral Mass Spectrometer (INMS) of the density and structure of Enceladus' south polar plume during the E3 and E5 flybys on 12 March and 9 October 2008. Using a Monte Carlo simulation, we analyze the dependence of the INMS gas inlet transmittance on spacecraft pointing and the effect on the measure…
Latitudinal variations in Saturn's ionosphere: Cassini measurements and model comparisons
Galand, Marina; Moore, Luke; Mendillo, Michael +2 more
We present a study of latitudinal variations in Saturn's ionosphere using Cassini Radio Science Subsystem (RSS) measurements and Saturn-Thermosphere-Ionosphere-Model (STIM) simulations. On the basis of Cassini RSS observations, the peak electron density (NMAX) and the total electron content (TEC) both exhibit a clear increase with latit…
Magnetopause oscillations near the planetary period at Saturn: Occurrence, phase, and amplitude
Coates, A. J.; Andrews, D. J.; Cowley, S. W. H. +2 more
Using magnetic field and plasma electron data from ∼40 Cassini orbits that crossed Saturn's magnetopause during 2004-2007, we make a first systematic study of the magnetopause oscillations that are related to the oscillations in the magnetic field and plasma inside the magnetosphere near the ∼11 h planetary rotation period, here termed the magneto…
Rate of radial transport of plasma in Saturn's inner magnetosphere
Wilson, R. J.; Chen, Y.; Hill, T. W. +1 more
In the inner part of a rapidly rotating magnetosphere such as that of Saturn, the major observable signature of radial plasma convection is a series of longitudinally localized injections and simultaneous drift dispersions of hot tenuous plasma from the outer magnetosphere. The Cassini Plasma Spectrometer (CAPS) and the Cassini Magnetospheric Imag…