Search Publications
Northward field excursions in Saturn's magnetotail and their relationship to magnetospheric periodicities
Wilson, R. J.; Jackman, C. M.; McAndrews, H. J. +2 more
We present results from an investigation of Cassini encounters with Saturn's magnetotail current sheet, using magnetic field and plasma data. In the first of two intervals shown, small periodic changes in the north-south component of the magnetic field are matched by periodic density enhancements associated with the plasma sheet center. In the sec…
MESSENGER and Venus Express observations of the solar wind interaction with Venus
Barabash, Stas; Zhang, Tielong; Boardsen, Scott A. +15 more
At 23:08 UTC on 5 June 2007 the MESSENGER spacecraft reached its closest approach altitude of 338 km during its final flyby of Venus en route to its 2011 orbit insertion at Mercury. The availability of the simultaneous Venus Express solar wind and interplanetary magnetic field measurements provides a rare opportunity to examine the influence of up…
Saturn's equinoctial auroras
Dougherty, M. K.; Kurth, W. S.; Mitchell, D. G. +13 more
We present the first images of Saturn's conjugate equinoctial auroras, obtained in early 2009 using the Hubble Space Telescope. We show that the radius of the northern auroral oval is ∼1.5° smaller than the southern, indicating that Saturn's polar ionospheric magnetic field, measured for the first time in the ionosphere, is ∼17% larger in the nort…
Observations of Jovian polar auroral filaments
Nichols, J. D.; Clarke, J. T.; Grodent, D. +1 more
In this paper we report a phenomenon hitherto unobserved in Jupiter's ultraviolet polar auroras, specifically thin (∼0.6° wide), long-lived quasi-sun-aligned polar auroral filaments (PAFs) of brightness ∼100 kR spanning the highly variable region poleward of the main oval. This observation, made using Hubble Space Telescope images, is significant …
Giant vortices lead to ion escape from Venus and re-distribution of plasma in the ionosphere
Barabash, S.; Zhang, T. L.; Balikhin, M. A. +3 more
The interaction of the solar wind with Venus has a significant influence on the evolution of its atmosphere. Due to the lack of an intrinsic planetary magnetic field, there is direct contact between the fast flowing solar wind and the Venusian ionosphere. This leads to a number of different types of atmospheric escape process. Using Venus Express …
A sporadic layer in the Venus lower ionosphere of meteoric origin
Pätzold, M.; Christou, A. A.; Bird, M. K. +4 more
The Venus Express Radio Science (VeRa) experiment aboard Venus Express has detected, by means of radio occultation, distinct, low-lying layers of electron density below the base (115 km altitude) of the ionosphere of Venus. A plausible origin of these lowest layers is ionization by the influx of meteoroids into the atmosphere. The layers appeared …
Discovery of lake-effect clouds on Titan
Brown, R. H.; Baines, K. H.; Clark, R. N. +5 more
Images from instruments on Cassini as well as from telescopes on the ground reveal the presence of sporadic small-scale cloud activity in the cold late-winter north polar region of Saturn's large moon Titan. These clouds lie underneath the previously discovered uniform polar cloud attributed to a quiescent ethane cloud at ~40 km and appear confine…
Plasma wake of Tethys: Hybrid simulations versus Cassini MAG data
Dougherty, M. K.; Saur, J.; Neubauer, F. M. +2 more
The interaction between Saturn's fifth largest satellite, Tethys, and the corotating plasma of the inner magnetosphere has been studied with a three-dimensional hybrid simulation. Since Tethys possesses neither an intrinsic magnetic field nor a substantial ionosphere, the moon's surface is directly exposed to the impinging plasma. This leads to th…
Positive identification of lake strandlines in Shalbatana Vallis, Mars
Hynek, Brian M.; Di Achille, Gaetano; Searls, Mindi L.
Remote sensing studies of possible Martian paleolakes have hinted at the presence of paleoshorelines on Mars, although have never been unequivocally identified. Recently-acquired sub-meter scale High Resolution Imaging Science Experiment (HiRISE) images of Shalbatana Vallis reveal the first direct evidence of strandlines along a delta formed withi…
Signatures of field-aligned currents in Saturn's nightside magnetosphere
Coates, A. J.; Dougherty, M. K.; Khurana, K. K. +4 more
We report first results of a survey of near-simultaneous and near-conjugate magnetic field perturbations observed over Saturn's northern and southern nightside auroral regions on ∼40 periapsis passes of the Cassini spacecraft during 2008. Structured azimuthal fields that are generally anti-symmetric north and south were observed at auroral latitud…