Search Publications
A fracture history on Enceladus provides evidence for a global ocean
Patthoff, D. Alex; Kattenhorn, Simon A.
The region surrounding the south pole of Saturn's moon Enceladus shows a young, pervasively fractured surface that emanates enough heat to be detected by the Cassini spacecraft. To explain the elevated heat and eruptive icy plumes originating from large cracks (informally called “tiger stripes”) in the surface, many models implicitly assume a glob…
Compositional diversity at Theophilus Crater: Understanding the geological context of Mg-spinel bearing central peaks
Head, J. W.; Dhingra, D.; Pieters, C. M. +3 more
Analysis of high resolution Moon Mineralogy Mapper (M3) data reveals the presence of a prominent Mg-spinel-rich lithology in the central peaks of Theophilus crater on the lunar nearside. Other peak-associated lithologies are comprised of plagioclase, olivine, and pyroxene-bearing materials. A consistent spatial association of Mg-spinel …
Average magnetotail electron and proton pitch angle distributions from Cluster PEACE and CIS observations
Dandouras, I.; Fazakerley, A. N.; Owen, C. J. +2 more
We present results from the first systematic survey of proton and electron pitch angle distributions in the magnetotail, based on Cluster CIS and PEACE data binned by proton plasma β (βp). The proton distributions conform to the canonical picture of magnetotail ions - a boundary layer made up of Earthward streaming and bidirectional fie…
Quasi-periodic polar flares at Jupiter: A signature of pulsed dayside reconnections?
Bonfond, B.; Vogt, M. F.; Gérard, J. -C. +3 more
The most dynamic part of the Jovian UV aurora is located inside the main auroral oval. This region is known to regularly show localized but dramatic enhancements on timescales of several tens of seconds, called polar flares. They have often been associated with the polar cusp, based on their location in the polar cap. The present study is based on…
Excitation of banded whistler waves in the magnetosphere
Gary, S. Peter; Liu, Kaijun; Winske, Dan
Linear kinetic dispersion analysis and a two-dimensional electromagnetic particle-in-cell simulation are performed to demonstrate a possible excitation mechanism of banded whistler waves in the magnetosphere outside of the plasmapause. Whistler waves in the lower and the upper bands can be generated simultaneously by the whistler anisotropy instab…
Bipolar electric field signatures of reconnection separatrices for a hydrogen plasma at realistic guide fields
Divin, A.; Goldman, M. V.; Newman, D. L. +2 more
In preparation for the MMS mission we ask the question: how common are bipolar signatures linked to the presence of electron holes along separatrices emanating from reconnection regions? To answer this question, we conduct massively parallel simulations for realistic conditions and for the hydrogen mass ratio in boxes larger than considered in sim…
The evolution of Titan's detached haze layer near equinox in 2009
West, Robert A.; Turtle, Elizabeth P.; Lavvas, Panayotis +5 more
Saturn's moon Titan has a massive atmosphere laden with layers of photochemical haze. We report a recent dramatic change in the vertical structure of this haze, with a persistent ‘detached’ layer dropping in altitude from over 500 km to only 380 km between 2007 and 2010. The detached haze layer appears to be a well-defined tracer for Titan's merid…
Evolution of the equatorial oscillation in Saturn's stratosphere between 2005 and 2010 from Cassini/CIRS limb data analysis
Flasar, F. M.; Bézard, B.; Fouchet, T. +2 more
We present an analysis of thermal infrared spectra acquired in limb viewing geometry by Cassini/CIRS in February 2010. We retrieve vertical profiles of Saturn's stratospheric temperature from 20 hPa to 10-2 hPa, at 9 latitudes between 20°N and 20°S. Using the gradient thermal wind equation, we derive a map of the zonal wind field. Both …
On the relation between plasma escape and the Martian crustal magnetic field
Barabash, S.; Lundin, R.; Yamauchi, M. +2 more
Data from ASPERA-3 on Mars Express is used to study the geographic distribution of ionospheric O+ outflow and escape from Mars. Of particular interest is how the ion outflow relates to the crustal magnetic field regions facing the dayside, flank, and nightside of Mars. The most intense O+ fluxes are generated on the dayside a…
A statistical study of the propagation characteristics of whistler waves observed by Cluster
Khotyaintsev, Yuri V.; Agapitov, Oleksiy; Krasnoselskikh, Vladimir +1 more
VLF waves play a crucial role in the dynamics of radiation belts, and are responsible for the loss and the acceleration of energetic electrons. Modeling wave-particle interactions requires the best possible knowledge for how wave energy and wave-normal directions are distributed in L-shells and for the magnetic latitudes of different magnetic acti…