Search Publications
Field-aligned currents in Saturn's northern nightside magnetosphere: Evidence for interhemispheric current flow associated with planetary period oscillations
Coates, A. J.; Dougherty, M. K.; Alexeev, I. I. +6 more
We investigate the magnetic perturbations associated with field-aligned currents observed on 34 Cassini passes over the premidnight northern auroral region during 2008. These are found to be significantly modulated not only by the northern planetary-period oscillation (PPO) system, similar to the southern currents by the southern PPO system found …
Characteristics of ice grains in the Enceladus plume from Cassini observations
Ye, S. -Y.; Dong, Y.; Hill, T. W.
Ice grains in the Enceladus plume have been observed by several Cassini instruments during many Enceladus encounters. In this paper we study the ice grains ranging from less than one nanometer to micrometers in size based on multiple instrument observations. We have analyzed the nanograin data from the E17 and E18 Cassini Plasma Spectrometer (CAPS…
Internally driven large-scale changes in the size of Saturn's magnetosphere
Coates, A. J.; Dougherty, M. K.; Thomsen, M. F. +7 more
Saturn's magnetic field acts as an obstacle to solar wind flow, deflecting plasma around the planet and forming a cavity known as the magnetosphere. The magnetopause defines the boundary between the planetary and solar dominated regimes, and so is strongly influenced by the variable nature of pressure sources both outside and within. Following fro…
Electrostatic solitary waves observed at Saturn by Cassini inside 10 Rs and near Enceladus
Gurnett, D. A.; Pickett, J. S.; Jones, G. H. +5 more
We have analyzed the Cassini Radio and Plasma Wave Science Wideband Receiver (WBR) data specifically looking for the presence of bipolar electrostatic solitary waves (ESWs). Typical examples of these ESWs are provided to show that when they are present, several of them may be detected over a few to several millisecond time span. We carried out an …
Down-tail mass loss by plasmoids in Jupiter's and Saturn's magnetospheres
Jackman, C. M.; Nichols, J. D.; Cowley, S. W. H.
Recent estimates of the plasma mass-loss rates by the formation and down-tail propagation of plasmoids observed in the plasma sheet in Jupiter's and Saturn's magnetosphere fall short of inner moon source rates by at least an order of magnitude. Here we argue that on the time scale between large-scale disconnection events, ~15 h at Jupiter and ~45 …
Plasmapause formation at Saturn
Coates, A. J.; Thomsen, M. F.; Jackman, C. M. +3 more
Cassini observations during a rapid, high-latitude, dawnside pass from Saturn's lobe to inner magnetosphere on 25 June 2009 provide strong evidence for the formation of a "plasmapause" at Saturn by Vasyliunas-type nightside reconnection of previously mass-loaded flux tubes. A population of hot, tenuous plasma that lies between the lobe and the den…
An empirical approach to modeling ion production rates in Titan's ionosphere I: Ion production rates on the dayside and globally
Edberg, N. J. T.; Waite, J. H.; Cravens, T. E. +9 more
Titan's ionosphere is created when solar photons, energetic magnetospheric electrons or ions, and cosmic rays ionize the neutral atmosphere. Electron densities generated by current theoretical models are much larger than densities measured by instruments on board the Cassini orbiter. This model density overabundance must result either from overpro…
Cassini VIMS observations of H3+ emission on the nightside of Jupiter
Baines, Kevin H.; Brown, Robert H.; O'Donoghue, James +10 more
We present the first detailed analysis of H3+ nightside emission from Jupiter, using Visual and Infrared Mapping Spectrometer (VIMS) data from the Cassini flyby in 2000-2001, producing the first Jovian maps of nightside H3+ emission, temperature, and column density. Using these, we identify and character…
Sustained lobe reconnection in Saturn's magnetotail
Thomsen, M. F.; Jackman, C. M.; Kurth, W. S. +3 more
The degree to which solar wind driving may affect Saturn's magnetosphere is not yet fully understood. We present observations that suggest that under some conditions the solar wind does govern the character of the plasma sheet in Saturn's outer magnetosphere. On 16 September 2006, the Cassini spacecraft, at a radial distance of 37 Rs ne…
Survey of Saturn Z-mode emission
Gurnett, D. A.; Persoon, A. M.; Wahlund, J. -E. +6 more
Because of the role of Z-mode emission in the diffusive scattering and resonant acceleration of electrons, we conduct a survey of intensity in the Saturn inner magnetosphere. Z mode is primarily observed as "5 kHz" narrowband emission in the lower density regions where the ratio of cyclotron to plasma frequency, fc/fp > 1 …