Search Publications
Bursty magnetic reconnection at Saturn's magnetopause
Coates, A. J.; Dougherty, M. K.; Hasegawa, H. +6 more
We infer the evolution of magnetopause reconnection from simultaneous in situ magnetopause crossings and auroral observations by Cassini on 19 July 2008. Depending on the magnetosheath field, it proceeds from (i) the high-latitude lobe, producing a cusp spot in the aurora, to (ii) lower latitude but north of Cassini, evidenced by an enhancement of…
Cassini CAPS-ELS observations of negative ions in Titan's ionosphere: Trends of density with altitude
Lewis, G. R.; Coates, A. J.; Jones, G. H. +2 more
Observations with the Electron Spectrometer sensor of the Cassini Plasma Spectrometer (CAPS-ELS) have revealed the existence of negative ions in Titan's ionosphere. Negative ions are observed during encounters whenever the instrument points in the ram direction at altitudes 950-1400 km. Complex hydrocarbon and nitrile chemical processes are believ…
Auroral signatures of multiple magnetopause reconnection at Saturn
Bonfond, B.; Gérard, J. -C.; Grodent, D. +5 more
Auroral observations capture the ionospheric response to dynamics of the whole magnetosphere and may provide evidence of the significance of reconnection at Saturn. Bifurcations of the main dayside auroral emission have been related to reconnection at the magnetopause and their surface is suggested to represent the amount of newly opened flux. Thi…
An unidentified emission in Titan's upper atmosphere
López-Puertas, M.; D'Aversa, E.; García-Comas, M. +4 more
We have analyzed limb daytime observations of Titan's upper atmosphere at 3.3 µm, acquired by the visual-infrared mapping spectrometer (VIMS) on Cassini. They were previously studied by García-Comas et al. (2011) to derive CH4 densities. Here, we report an unidentified emission peaking around 3.28 µm, hidden under the methan…
Extreme densities in Titan's ionosphere during the T85 magnetosheath encounter
Dougherty, M. K.; Roussos, E.; Garnier, P. +10 more
We present Cassini Langmuir probe measurements of the highest electron number densities ever reported from the ionosphere of Titan. The measured density reached 4310 cm-3 during the T85 Titan flyby. This is at least 500 cm-3 higher than ever observed before and at least 50% above the average density for similar solar zenith a…
Resonant diffusion of energetic electrons by narrowband Z mode waves in Saturn's inner magnetosphere
Ni, Binbin; Gu, Xudong; Ye, Sheng-Yi +1 more
<title type="main">Abstract<p label="1">Banded emissions near 5 and 20 kHz are observed by the Cassini Radio and Plasma Wave Science (RPWS) instrument and are identified as Z mode waves in the regions where the plasma frequency is below the electron gyrofrequency. Using wave parameters derived from Gaussian fits to the measured power s…
Compositional effects in Titan's thermospheric gravity waves
Cui, J.; Müller-Wodarg, I. C. F.; Lian, Y.
In Titan's upper atmosphere, the density profiles of several constituents (N2, CH4, H2, and 29N2) as measured by the Cassini Ion Neutral Mass Spectrometer show periodical structures which we interpret as internal gravity waves. Compositional effects are frequently seen in the data, in which th…
Longitude dependences of Saturn's ultraviolet aurora
Carbary, J. F.
on periodicities in the kilometric radio emissions, the Saturn Longitude System 4 (SLS4) was used to organize the far ultraviolet (120-150 nm) aurora observed by the Ultraviolet Imaging Spectrograph on the Cassini spacecraft. Individual Ultraviolet Imaging Spectrograph pixels were projected onto the ionosphere of Saturn, transformed into the SLS4 …
Saturn's magnetospheric refresh rate
Krupp, N.; Jackman, C. M.; Mitchell, D. G. +3 more
A 2-3 day periodicity observed in Jupiter's magnetosphere (superposed on the giant planet's 9.5 h rotation rate) has been associated with a characteristic mass-loading/unloading period at Jupiter. We follow a method derived by Kronberg et al. (<link href="#grl50530-bib-0016"/>) and find, consistent with their results, that this period is mos…
Probing IMF using nanodust measurements from inside Saturn's magnetosphere
Kempf, S.; Postberg, F.; Srama, R. +6 more
We present a new concept of monitoring the interplanetary magnetic field (IMF) by using in situ measurements of nanodust stream particles in Saturn's magnetosphere. We show that the nanodust detection pattern obtained inside the magnetosphere resembles those observed in interplanetary space and is associated with the solar wind compression regions…