Search Publications
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…
ACRIM-gap and total solar irradiance revisited: Is there a secular trend between 1986 and 1996?
Solanki, S. K.; Krivova, N. A.; Wenzler, T.
A gap in the total solar irradiance (TSI) measurements between ACRIM-1 and ACRIM-2 led to the ongoing debate on the presence or not of a secular trend between the minima preceding cycles 22 (in 1986) and 23 (1996). It was recently proposed to use the SATIRE model of solar irradiance variations to bridge this gap. When doing this, it is important t…
Dual periodicities in energetic electrons at Saturn
Krupp, N.; Krimigis, S. M.; Mitchell, D. G. +1 more
The fluxes of energetic electrons (110-365 keV) in Saturn's magnetosphere were subjected to Lomb periodogram analyses for 1677 days from late 2004 to the middle of 2009. The electrons generally exhibited strong periodicities at 10.82 hours and 10.60 hours for much of the ∼4.6 year interval. The longer period was generally present all the time, whi…
Regions associated with electron physics in asymmetric magnetic field reconnection
Pritchett, P. L.; Mozer, F. S.
Spatial relationships between regions containing signatures of electron physics in asymmetric reconnection with a guide field are examined using simulations and space observations that are in excellent agreement. These electron physics regions do not completely overlap, are not confined to sizes ∼electron skin depth, and do not surround the X-line…
On the elusive hot oxygen corona of Venus
Lammer, H.; Shematovich, V. I.; Lichtenegger, H. I. M. +2 more
After more than two years in orbit still no Venus Express observations were published concerning the hot oxygen corona of Venus which could verify the corresponding controversial observations of Venera 11 and PVO, three decades ago. Based on recent energy and mass dependent collision cross sections, the energy distributions of hot atomic oxygen cr…