Search Publications
Particle pressure, inertial force, and ring current density profiles in the magnetosphere of Saturn, based on Cassini measurements
Coates, A. J.; Krupp, N.; Dougherty, M. K. +9 more
We report initial results on the particle pressure distribution and its contribution to ring current density in the equatorial magnetosphere of Saturn, as measured by the Magnetospheric Imaging Instrument (MIMI) and the Cassini Plasma Spectrometer (CAPS) onboard the Cassini spacecraft. Data were obtained from September 2005 to May 2006, within ±0.…
First results from the Venetia Burney Student Dust Counter on the New Horizons mission
James, David; Horányi, Mihály; Poppe, Andrew +1 more
The Venetia Burney Student Dust Counter (SDC) onboard the New Horizons mission is an impact-based dust detector designed to map the size and spatial variability of the interplanetary dust population throughout the solar system. SDC consists of fourteen permanently polarized polyvinylidene fluoride detectors that register a charge upon impact by hy…
Detection of visible lightning on Saturn
Kurth, W. S.; West, R. A.; Fischer, G. +4 more
Until now, evidence for lightning on Saturn has been indirect - through radio emissions and cloud morphology. Here we report the first visible detection of lightning, on the night side on August 17, 2009 at -36.4° ± 0.1° planetocentric latitude and 10.6° ± 0.9° west longitude. No other locations produced lightning detectable by either imaging or r…
Magnitude of the Hall fields during magnetic reconnection
Egedal, J.; Daughton, W.; Drake, J. F. +3 more
In situ observation of the Earth's magnetosphere has identified Hall magnetic fields as a key signature of collisionless magnetic reconnection. The inflow portion of the reconnection diffusion region is further characterized by strong electron pressure anisotropy. These two features are tightly linked in a quantitative model, which is verified usi…
Cause of super-thermal electron heating during magnetotail reconnection
Eastwood, J. P.; Lin, R. P.; Øieroset, M. +5 more
We present a candidate mechanism for the energization of super-thermal electrons during magnetic reconnection in the Earth's magnetotail. By analyzing in-situ measurements of electron distribution functions we characterize the relative energy gain of the electrons as a function of energy, Δ${\cal{E}(${\cal{E}). For all the events considered the hi…
Librational response of Enceladus
Rambaux, Nicolas; Karatekin, Özgür; Castillo-Rogez, Julie C. +1 more
Physical librations could significantly contribute to Enceladus' geophysics through their influence on tidal stress. Therefore it is important to determine their behavior and the present paper is devoted to estimating Enceladus' libration in longitude. In a rotational model of Enceladus with no global ocean, we introduce the main perturbative term…
Electron density and temperature measurements in the cold plasma environment of Titan: Implications for atmospheric escape
Dougherty, M. K.; Wahlund, J. -E.; Edberg, N. J. T. +4 more
We present electron temperature and density measurements of Titan's cold ionospheric plasma from the Langmuir probe instrument on Cassini from 52 flybys. An expression of the density as a function of temperature is presented for altitudes below two Titan radii. The density falls off exponentially with increased temperature as log(ne) = …
Magnetic reconnection and cold plasma at the magnetopause
Laitinen, T.; Nilsson, H.; André, M. +5 more
We report on detailed observations by the four Cluster spacecraft of magnetic reconnection and a Flux Transfer Event (FTE) at the magnetopause. We detect cold (eV) plasma at the magnetopause with two independent methods. We show that the cold ions can be essential for the electric field normal to the current sheet in the separatrix region at the e…
Earthward electric field in the magnetotail: Cluster observations and theoretical estimates
Petrukovich, A. A.; Zelenyi, L. M.; Artemyev, A. V.
In this paper we present an experimental evidence of the existence of the earthward electric field in the thin current sheet of the Earth magnetotail. This field plays an essential role in the redistribution of observed intensities of cross-tail proton and electron currents. We consider the statistics of 59 thin current sheet crossings observed by…
A plasmapause-like density boundary at high latitudes in Saturn's magnetosphere
Gurnett, D. A.; Persoon, A. M.; Krupp, N. +8 more
Here we report the discovery of a well-defined plasma density boundary at high latitudes in Saturn's magnetosphere. The boundary separates a region of relatively high density at L less than about 8 to 15 from a region with densities nearly three orders of magnitude lower at higher L values. Magnetic field measurements show that strong field-aligne…