Search Publications
Magnetic signatures of Kelvin-Helmholtz vortices on Saturn's magnetopause: Global survey
Wilson, R. J.; Delamere, P. A.; Bagenal, F. +1 more
Saturn's rapid rotation combined with relatively weak magnetic fields in the outer magnetosphere and sheath lead to conditions that are favorable for the Kelvin-Helmholtz (KH) instability. A Kelvin-Helmholtz unstable magnetopause boundary has important consequences for Saturn's interaction with the solar wind due to mass, momentum, and energy tran…
Multispectral simultaneous diagnosis of Saturn's aurorae throughout a planetary rotation
Lamy, L.; Badman, S. V.; Brandt, P. C. +6 more
From 27 to 28 January 2009, the Cassini spacecraft remotely acquired combined observations of Saturn's southern aurorae at radio, ultraviolet, and infrared wavelengths, while monitoring ion injections in the middle magnetosphere from energetic neutral atoms. Simultaneous measurements included the sampling of a full planetary rotation, a relevant t…
Conditions at the magnetopause of Saturn and implications for the solar wind interaction
Delamere, P. A.; Bagenal, F.; Desroche, M. +1 more
Using idealized models of the magnetosheath and magnetospheric magnetic fields, plasma densities, and plasma flow, we test for the steady state viability of processes mediating the interaction between the solar wind and the magnetosphere of Saturn. The magnetopause is modeled as an asymmetric paraboloid with a standoff distance of ∼25 RS
Evidence from radial velocity measurements of a global electric field in Saturn's inner magnetosphere
Wilson, R. J.; Delamere, P. A.; Bagenal, F. +3 more
The presence of a convection pattern in the Saturnian inner magnetosphere was first observed in moon signatures that were displaced from their expected locations. A noon to midnight directed electric field can account for these positional offsets, and also can explain asymmetries found in plasma temperatures between the day and night sides. By ass…
The plasma density distribution in the inner region of Saturn's magnetosphere
Gurnett, D. A.; Persoon, A. M.; Kurth, W. S. +3 more
Electron density measurements derived from the upper hybrid resonance frequency have been obtained from the Cassini Radio and Plasma Wave Science experiment over a 7 year period from 28 October 2004 through 7 November 2011. Additional density measurements inside the orbit of Enceladus and outside the orbit of Rhea have made it possible to expand a…
Cassini/CAPS observations of duskside tail dynamics at Saturn
Thomsen, M. F.; Wilson, R. J.; Tokar, R. L. +2 more
properties of Saturn's premidnight tail region are surveyed using Cassini/Cassini Plasma Spectrometer (CAPS) ion observations from 2010. Only low-latitude (|lat| < 6°) intervals in which the CAPS viewing was roughly symmetric inward and outward around the corotation direction are used. Our numerical moments algorithm returns nonzero ion density…
Simultaneous conjugate observations of small-scale structures in Saturn's dayside ultraviolet auroras: Implications for physical origins
Yeoman, T. K.; Nichols, J. D.; Cowley, S. W. H. +2 more
Small-scale features in Saturn's dayside UV auroras are examined using images obtained on 32 Hubble Space Telescope visits close to Saturn equinox when both northern and southern emissions were simultaneously observed, allowing their interhemispheric conjugacy to be investigated. Eastward-propagating patches in the dawn-to-noon sector were observe…
Ordering of injection events within Saturnian SLS longitude and local time
Gurnett, D. A.; Hospodarsky, G. B.; Kennelly, T. J. +1 more
Periodicities similar to the Saturn kilometric radio (SKR) emissions have been observed throughout the magnetosphere in both the magnetic field and the plasma. An outstanding question is what mechanism links these periodicities between the inner and outer magnetospheres. It had been postulated that the interchange instability, where narrow injecti…
Particle and magnetic field properties of the Saturnian magnetosheath: Presence and upstream escape of hot magnetospheric plasma
Coates, A. J.; Dougherty, M. K.; Thomsen, M. F. +6 more
We analyze plasma, energetic particle, and magnetic field data from all available Cassini passes through the Saturnian magnetosheath between July 2004 and July 2011 and provide a statistical overview of particle and field properties. The results show that magnetosheath plasma has an average number density of ~0.1 cm-3 and a temperature …
Long-term modulations of Saturn's auroral radio emissions by the solar wind and seasonal variations controlled by the solar ultraviolet flux
Cecconi, B.; Lamy, L.; Fujimoto, M. +9 more
Saturn's auroral activities have been suggested to be controlled by the seasonal variations of the polar ionospheric conductivities and atmospheric conditions associated with the solar extreme ultraviolet (EUV) flux. However, they have not yet been explained self-consistently by only the seasonal solar EUV effects. This study investigates the long…