Search Publications
Measurements of the ion escape rates from Venus for solar minimum
Fedorov, A.; Barabash, S.; Lundin, R. +4 more
We report the first direct measurements of the Venusian atmospheric erosion rate due to the interaction with the solar wind. The erosion through the ion escape is determined during the period of the minimum solar activity from 24 May 2006 to 12 December 2007. The ion fluxes are measured in the energy range 10 eV to 25 keV by an ion mass spectromet…
Atmospheric erosion of Venus during stormy space weather
Fedorov, A.; Barabash, S.; Futaana, Y. +9 more
We study atmospheric escape from Venus during solar minimum conditions when 147 corotating interaction regions (CIRs) and interplanetary coronal mass ejections (ICMEs) combined impact on the planet. This is the largest study to date of the effects of stormy space weather on Venus and we show for the first time statistically that the atmosphere of …
Suprathermal electron spectra in the Venus ionosphere
Coates, A. J.; Zhang, T. L.; Galand, M. +2 more
In this study, a multistream kinetic model is used to derive the suprathermal electron intensity in the Venus ionosphere, to be compared with the observations made by the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-4) Electron Spectrometer (ELS) instrument onboard Venus Express (VEx) on 18 May 2006. Input parameters of the model are chos…
Proton cyclotron wave generation mechanisms upstream of Venus
Zhang, T. L.; Volwerk, M.; Mazelle, C. +3 more
Long-term observations of proton cyclotron waves in the upstream region of Venus raise the question of under which general solar wind conditions these waves are generated and maintained. The waves are characterized by their occurrence at the local proton cyclotron frequency and left-hand polarization, both in the spacecraft frame. Magnetometer dat…
O+ outflow channels around Venus controlled by directions of the interplanetary magnetic field: Observations of high energy O+ ions around the terminator
Barabash, S.; Futaana, Y.; Yamauchi, M. +5 more
Using the plasma and the magnetic field data measured by the ASPERA-4 (Analyzer of Space Plasma and Energetic Atoms) and the magnetometer (MAG) onboard Venus Express between June 2006 and December 2008, positions of high energy O+ fluxes (>100 eV) near the Venus terminator are examined for two different interplanetary magnetic field …
Tracking corotating interaction regions from the Sun through to the orbit of Mars using ACE, MEX, VEX, and STEREO
Fränz, M.; Davies, J. A.; Lester, M. +3 more
We study the propagation of corotating interaction regions (CIRs) through the inner heliosphere during the solar minimum of 2007-2008 using the Advanced Composition Explorer (ACE), Mars Express (MEX), Venus Express (VEX), and the Solar Terrestrial Relations Observatory (STEREO). We present observations of 24 CIRs observed during the period from 1 …
Unusual nonlinear waves in the Venusian magnetosheath
Zhang, T. L.; Walker, S. N.; Balikhin, M. A. +4 more
Within the Venusian magnetosheath, Venus Express has observed the existence of high-amplitude, nonlinear waves which have been interpreted as large-scale nonlinear rotational structures within the magnetic field. A number of mechanisms have been proposed that can be used to explain their origin. Venus Express data have been searched for other exam…
Plasma transition at the flanks of the Venus ionosheath: Evidence from the Venus Express data
Barabash, S.; Lundin, R.; Zhang, T. L. +6 more
Measurements conducted with the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-4) instrument in the Venus Express spacecraft reveal the presence of a plasma transition within a boundary layer that extends along at the flanks of the Venus ionosheath and where the solar wind exhibits changes similar to those reported from previous missions (M…
Space charge effects and arc properties of simulated lightning on Venus
Robledo-Martinez, A.; Sobral, H.; Ruiz-Meza, A.
An experimental investigation of the physical properties of lightning on Venus was carried out by applying fast impulses to a pressurized (1-2.8 atm) CO2-N2 gas mix. The maximum current employed in the experiments was 2.8 kA. It was found that the pressure has a marked effect on the measured electric field. This effect is mos…