Search Publications
Multi-instrument analysis of electron populations in Saturn's magnetosphere
Schippers, P.; André, N.; Gurnett, D. A. +10 more
We analyze the radial distribution of electron populations inside 20 Rs in Saturn's magnetosphere, and we calculate moments for these populations by a forward modeling method using composite spectra produced by the CAPS/ELS (0.6 eV to 26 keV) and the MIMI/LEMMS (15 keV to 10 MeV) instruments on board Cassini. We first calculate and harm…
An update to a Saturnian longitude system based on kilometric radio emissions
Gurnett, D. A.; Kurth, W. S.; Averkamp, T. F. +2 more
The period of Saturn kilometric radiation modulation as determined by Voyager forms the basis for a longitude system (SLS) recognized by the International Astronomical Union. However, Ulysses and Cassini observations have shown that this modulation period varies by the order of one percent on timescales of a few years and, hence, does not represen…
Warping of Saturn's magnetospheric and magnetotail current sheets
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +5 more
The magnetotails of Jupiter and Earth are known to be hinged so that their orientation is controlled by the magnetic field of the planet at small distances and asymptotically approach the direction of the flow of the solar wind at large distances. In this paper we present Cassini observations showing that Saturn's magnetosphere is also similarly h…
Cassini plasma spectrometer thermal ion measurements in Saturn's inner magnetosphere
Thomsen, M. F.; Wilson, R. J.; Tokar, R. L. +3 more
Plasma data from the Cassini Plasma Spectrometer experiment are analyzed using a robust forward modeling technique for dayside equatorial orbits within the range 5.5 to 11 Saturn radii (1 RS = 60,268 km). It is assumed the measured ion data may be represented by two anisotropic Maxwellian distributed species, H+ and a water g…
Origin of Saturn's aurora: Simultaneous observations by Cassini and the Hubble Space Telescope
Coates, A. J.; Dougherty, M. K.; Nichols, J. D. +9 more
Outer planet auroras have been imaged for more than a decade, yet understanding their physical origin requires simultaneous remote and in situ observations. The first such measurements at Saturn were obtained in January 2007, when the Hubble Space Telescope imaged the ultraviolet aurora, while the Cassini spacecraft crossed field lines connected t…
Saturn kilometric radiation: Average and statistical properties
Gurnett, D. A.; Kurth, W. S.; Cecconi, B. +3 more
Since Cassini entered Saturn's magnetosphere in July 2004, the auroral Saturnian kilometric radiation (SKR), which dominates the kronian radio spectrum, is observed quasi-continuously. Consecutive orbits of the spacecraft covered distances to Saturn down to 1.3 Saturn radii, all local times and, since December 2006, latitudes as high as 60°. On th…
Planetary period oscillations in Saturn's magnetosphere: Phase relation of equatorial magnetic field oscillations and Saturn kilometric radiation modulation
Dougherty, M. K.; Andrews, D. J.; Cowley, S. W. H. +3 more
We examine the planetary-period oscillations in Saturn's magnetic field observed by the Cassini spacecraft on 23 near-equatorial periapsis passes in the inner magnetosphere spanning October 2004 to July 2006. Overall, we find that the phase of the magnetic oscillations is well organized by the long-timescale modulation phase of Saturn kilometric r…
Evidence for reconnection at Saturn's magnetopause
Coates, A. J.; Dougherty, M. K.; Thomsen, M. F. +4 more
Observations of Saturn's magnetopause by the Cassini Plasma Spectrometer (CAPS) and magnetometer have revealed clear instances of magnetic reconnection signatures, two of which are described here. Both encounters occurred at the equator in the prenoon sector as Cassini was exiting the magnetosphere. Evidence of heating in the electrons and ions is…
Saturn's magnetodisc current sheet
Russell, C. T.; Dougherty, M. K.; Khurana, K. K. +5 more
Pioneer 11 observations from the dawn flank of Saturn's magnetosphere provided evidence for a thin equatorial current sheet. Magnetometer data from the Cassini orbiter have also revealed the presence of this current sheet and shown it to be a consistent feature of the dawn flank. Arridge et al. (2007) recently investigated the stress balance in th…
Oscillation of Saturn's southern auroral oval
Nichols, J. D.; Clarke, J. T.; Cowley, S. W. H. +5 more
Near-planetary-period oscillations in the Cassini plasma and magnetic field data have been observed throughout Saturn's magnetosphere despite the fact that Saturn's internal magnetic field is apparently highly axisymmetric. In addition, the period of the Saturn kilometric radiation has been shown to vary over time. In this paper we present results…