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Mars Express and Venus Express multi-point observations of geoeffective solar flare events in December 2006
Coates, A. J.; Kallio, E.; Fedorov, A. +50 more
In December 2006, a single active region produced a series of proton solar flares, with X-ray class up to the X9.0 level, starting on 5 December 2006 at 10:35 UT. A feature of this X9.0 flare is that associated MeV particles were observed at Venus and Mars by Venus Express (VEX) and Mars Express (MEX), which were ∼80° and ∼125° east of the flare s…
Initial Venus Express magnetic field observations of the Venus bow shock location at solar minimum
Barabash, S.; Russell, C. T.; Zhang, T. L. +10 more
In this study, magnetic field measurements obtained by the Venus Express spacecraft are used to determine the bow shock position at solar minimum. The best fit of bow shock location from solar zenith angle 20-120° gives a terminator bow shock location of 2.14 RV (1 RV=6052 km) which is 1600 km closer to Venus than the 2.40 R<…
Location of the bow shock and ion composition boundaries at Venus—initial determinations from Venus Express ASPERA-4
Coates, A. J.; Kallio, E.; Fedorov, A. +52 more
For the first time since 1992 when the Pioneer Venus Orbiter (PVO) ceased to operate, there is again a plasma instrument in orbit around Venus, namely the ASPERA-4 flown on Venus Express (inserted into an elliptical polar orbit about the planet on April 11, 2006). In this paper we report on measurements made by the ion and electron sensors of ASPE…
Ionospheric photoelectrons at Venus: Initial observations by ASPERA-4 ELS
Coates, A. J.; Kallio, E.; Fedorov, A. +46 more
We report the detection of electrons due to photo-ionization of atomic oxygen and carbon dioxide in the Venus atmosphere by solar helium 30.4 nm photons. The detection was by the Analyzer of Space Plasma and Energetic Atoms (ASPERA-4) Electron Spectrometer (ELS) on the Venus Express (VEx) European Space Agency (ESA) mission. Characteristic peaks i…
Initial Venus Express magnetic field observations of the magnetic barrier at solar minimum
Barabash, S.; Russell, C. T.; Zhang, T. L. +8 more
Although there is no intrinsic magnetic field at Venus, the convected interplanetary magnetic field piles up to form a magnetic barrier in the dayside inner magnetosheath. In analogy to the Earth's magnetosphere, the magnetic barrier acts as an induced magnetosphere on the dayside and hence as the obstacle to the solar wind. It consists of regions…
Venus upper atmospheric CO, temperature, and winds across the afternoon/evening terminator from June 2007 JCMT sub-millimeter line observations
Clancy, R. T.; Sandor, B. J.; Moriarty-Schieven, G. H.
The Venus mesosphere constitutes a highly variable transition region between the zonal rotation of the lower atmosphere and the diurnal circulation of the upper atmosphere. It further serves as the primary photochemical region of the Venus atmosphere. We obtained James Clerk Maxwell Telescope (JCMT, Mauna Kea Hawaii) sub-millimeter line observatio…
Comparative analysis of Venus and Mars magnetotails
Coates, A. J.; Kallio, E.; Fedorov, A. +47 more
We have an unique opportunity to compare the magnetospheres of two non-magnetic planets as Mars and Venus with identical instrument sets Aspera-3 and Aspera-4 on board of the Mars Express and Venus Express missions. We have performed both statistical and case studies of properties of the magnetosheath ion flows and the flows of planetary ions behi…
Venus upper atmosphere winds from ground-based heterodyne spectroscopy of CO 2 at 10µm wavelength
Sornig, M.; Livengood, T.; Sonnabend, G. +4 more
We report observations of Venus atmospheric wind near 110 km altitude by means of high-resolution mid-infrared spectroscopy. Data were acquired May 28-June 4, 2007 at the McMath-Pierce Solar Telescope (Kitt Peak, Arizona, USA), during a coordinated ground-based observing campaign in support of Venus Express. The Cologne Tuneable Heterodyne Infrare…
Monitoring Venus’ mesospheric winds in support of Venus Express: IRAM 30-m and APEX observations
Lellouch, E.; Moreno, R.; Moullet, A. +1 more
We report on direct wind measurements in Venus' mesosphere (90-115 km), performed in support of Venus Express, and based on CO millimeter observations. Most observations, sampling the CO(2-1) and CO(1-0) lines, were acquired with the IRAM 30-m telescope, over four distinct periods: (i) Summer 2006; (ii) May-June 2007, in association with the coord…
Mesospheric vertical thermal structure and winds on Venus from HHSMT CO spectral-line observations
Hartogh, Paul; Jarchow, Christopher; Rengel, Miriam
We report vertical thermal structure and wind velocities in the Venusian mesosphere retrieved from carbon monoxide ( 12CO J=2-1 and 13CO J=2-1) spectral line observations obtained with the Heinrich Hertz Submillimeter Telescope (HHSMT). We observed the mesosphere of Venus from two days after the second Messenger flyby of Venu…