Search Publications
Disappearing induced magnetosphere at Venus: Implications for close-in exoplanets
Russell, C. T.; Lammer, H.; Zhang, T. L. +4 more
The solar wind interaction with a planetary atmosphere produces a magnetosphere-like structure near the planet whether or not the planet has an intrinsic global magnetic field. In the case of planets like Venus or Mars, which have no global intrinsic magnetic field but possess a significant atmosphere, a magnetosphere is induced in the highly cond…
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…
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 …
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…
Vortex circulation on Venus: Dynamical similarities with terrestrial hurricanes
Piccioni, Giuseppe; Markiewicz, Wojciech J.; Limaye, Sanjay S. +3 more
Some dynamical and morphological similarities exist between the vortex organization of the atmosphere in the northern and southern hemispheres of Venus and the tropical cyclones/hurricanes on Earth. An S-shape feature detected in the center of the vortices on Venus from Pioneer Venus Orbiter and Venus Express observations has also been seen in tro…
Hydrogen in the extended Venus exosphere
Zhang, T. L.; Volwerk, M.; Bertaux, J. L. +4 more
The nearly absence of water in the atmosphere of Venus is a major difference to the situation at Earth. The actual content of hydrogen in the exosphere is still an open issue, since no in situ measurements are available yet. A different method uses the presence of proton cyclotron waves as an early tracer of ionized planetary hydrogen picked-up by…
Magnetosheath fluctuations at Venus for two extreme orientations of the interplanetary magnetic field
Zhang, T. L.; Wang, C.; Baumjohann, W. +3 more
Using the magnetosheath crossings of Venus Express on two consecutive days, we investigate magnetic fluctuations in the same locations for two extreme interplanetary magnetic field orientations, i.e., nearly along and nearly perpendicular to the solar wind flow. It is shown that the properties of the fluctuations are drastically different at basic…
Modeling the response of the induced magnetosphere of Venus to changing IMF direction using MESSENGER and Venus Express observations
Boardsen, Scott A.; Gloeckler, George; Ho, George C. +14 more
The second MESSENGER flyby of Venus on 5 June 2007 provided a new opportunity to study the response of the induced magnetosphere of the planet to changes in the direction of the interplanetary magnetic field (IMF). At the time of the MESSENGER flyby, the European Space Agency's Venus Express spacecraft was located outside the magnetosphere and pro…
Tsallis distribution of the interplanetary magnetic field at 0.72 AU: Venus Express observation
Zhang, T. L.; Wang, C.; Li, X. Y.
Previous work shows that Probability Distribution Functions (PDFs) of the interplanetary magnetic field strength differences can be described by a single function - Tsallis distribution at Earth and beyond. Launch of Venus Express enables us to extend the application of Tsallis distribution to the inner heliosphere at 0.72 AU. This paper analyzes …