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Survey of Saturn's Magnetopause and Bow Shock Positions Over the Entire Cassini Mission: Boundary Statistical Properties and Exploration of Associated Upstream Conditions
Dougherty, M. K.; Thomsen, M. F.; Jackman, C. M.
The Cassini spacecraft orbited the planet Saturn from July 2004 to September 2017, and its varied orbital trajectory took it across the magnetopause and bow shock boundaries multiple times, at varying radial distances, local times, latitudes, and phases of the solar cycle. Here we present a comprehensive list of these boundary crossings, derived p…
Variability of Intra-D Ring Azimuthal Magnetic Field Profiles Observed on Cassini's Proximal Periapsis Passes
Dougherty, M. K.; Cowley, S. W. H.; Bunce, E. J. +4 more
We overview the properties of the azimuthal magnetic fields observed during the periapsis passes of the final 23 orbits of the Cassini spacecraft, including the partial orbit at end of mission, on near equatorial field lines passing inside of Saturn's D ring. The signatures are variable in form and amplitude, though generally approximately symmetr…
Cassini Radio Occultation Observations of Titan's Ionosphere: The Complete Set of Electron Density Profiles
Dalba, Paul A.; Withers, Paul
Titan's ionosphere is an important component of the moon's environment. Ionospheric densities above ≈900 km have been studied with in situ measurements, but few density profiles for lower altitudes has been reported. Here we report the generation of the complete set of twenty ionospheric electron density profiles from the Cassini Radio Science Sub…
Saturn's Plasmapause: Signature of Magnetospheric Dynamics
Coates, A. J.; Thomsen, M. F.
We explore the paradigm that Saturn's plasmapause marks the boundary between the magnetic flux tubes that have been circulating around the planet for some time, accumulating a dense load of Enceladus-sourced material, and those that have recently undergone tail reconnection, shedding the bulk of the cold plasma and retaining a more tenuous, heated…
The Structure of Planetary Period Oscillations in Saturn's Equatorial Magnetosphere: Results From the Cassini Mission
Wahlund, J. -E.; Andrews, D. J.; Cowley, S. W. H. +4 more
Saturn's magnetospheric magnetic field, planetary radio emissions, plasma populations, and magnetospheric structure are all known to be modulated at periods close to the assumed rotation period of the planetary interior. These oscillations are readily apparent despite the high degree of axisymmetry in the internally produced magnetic field of the …
Local Time Variation in the Large-Scale Structure of Saturn's Magnetosphere
Dougherty, M. K.; Arridge, C. S.; Guio, P. +3 more
The large-scale structure of Saturn's magnetosphere is determined by internal and external factors, including the rapid planetary rotation rate, significant internal hot and cold plasma sources, and varying solar wind pressure. Under certain conditions the dayside magnetospheric magnetic field changes from a dipolar to more disk-like structure, du…
Magnetic Field Observations on Cassini's Proximal Periapsis Passes: Planetary Period Oscillations and Mean Residual Fields
Dougherty, M. K.; Cowley, S. W. H.; Bunce, E. J. +4 more
We analyze periapsis pass magnetic field data from the final 23 orbits of the Cassini spacecraft at Saturn, uniquely encompassing auroral, subauroral, ring region, and intra-ring field lines, to determine the planetary period oscillations (PPOs) and mean residual fields in these regions. Dual modulation by northern and southern PPO systems is foun…
Solar Wind Dynamic Pressure Upstream From Saturn: Estimation From Magnetosheath Properties and Comparison With SKR
Thomsen, M. F.; Jackman, C. M.; Lamy, L.
An analytical method is developed by which measurements made by the Cassini spacecraft in Saturn's magnetosheath can be used to infer the upstream solar wind parameters, specifically the solar wind speed (Vsw) and the dynamic pressure (Pd). The method is validated by comparing the results with other estimates of these parameters, includ…
Survey of Saturn Whistler Mode Hiss Intensity
Kurth, W. S.; Averkamp, T. F.; Menietti, J. D.
We have conducted an extensive survey of whistler mode hiss emission at Saturn using nearly the complete data set from the Cassini Radio and Plasma Wave Science investigation. We distinguish the hiss emission by frequency and intensity threshold criteria. The survey includes all longitudes and latitudes >25° for r < 10 RS, limited…
Currents Associated With Saturn's Intra-D Ring Azimuthal Field Perturbations
Dougherty, M. K.; Cowley, S. W. H.; Bunce, E. J. +4 more
During the final 22 full revolutions of the Cassini mission in 2017, the spacecraft passed at periapsis near the noon meridian through the gap between the inner edge of Saturn's D ring and the denser layers of the planet's atmosphere, revealing the presence of an unanticipated low-latitude current system via the associated azimuthal perturbation f…