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Cluster multispacecraft determination of AKR angular beaming
Pickett, J. S.; Mutel, R. L.; Christopher, I. W.
Simultaneous observations of AKR emission using the four-spacecraft Cluster array were used to make the first direct measurements of the angular beaming patterns of individual bursts. By comparing the spacecraft locations and AKR burst locations, the angular beaming pattern was found to be narrowly confined to a plane containing the magnetic field…
Transient layers in the topside ionosphere of Mars
Gurnett, D. A.; Morgan, D. D.; Kopf, A. J. +1 more
Radar soundings from the MARSIS instrument on board the Mars Express spacecraft have shown that distinct layers can occur in the topside ionosphere of Mars, well above the main photo-ionization layer. These layers appear as cusps, or sometimes steps, in plots of the time delay as a function of frequency. Usually only one topside layer is observed,…
Surface brightness variations seen by VIRTIS on Venus Express and implications for the evolution of the Lada Terra region, Venus
Drossart, Pierre; Piccioni, Giuseppe; Helbert, Jörn +3 more
Venus Express is since April 11, 2006 in orbit around Venus. VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) has started only hours after orbit insertion to collect an immense and unique data set. Of special interest is the wavelength range from 1-1.5 microns which includes the ``atmospheric windows''. By averaging several hundred multi…
ENA periodicities at Saturn
Krimigis, S. M.; Mitchell, D. G.; Paranicas, C. +2 more
The Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft has observed energetic neutral atoms (ENA) at Saturn for three years from 2004 to 2007. The 20-50 keV hydrogen and 64-144 keV oxygen neutrals were examined for periodic behavior by projecting their images onto a plane perpendicular to Saturn's equatorial plane and summing the e…
Venus Express observes a new type of shock with pure kinematic relaxation
Zhang, T. L.; Balikhin, M. A.; Gedalin, M. +2 more
Collisionless shocks are present in the vicinity of many astrophysical objects such as supernova remnants, space jets, stars and planets immersed in the supersonic flow of stellar winds. Understanding the shock structure is crucial for understanding the processes of the redistribution of the upstream flow energy into accelerated particles and form…
Discovery of a transient radiation belt at Saturn
Krupp, N.; Jones, G. H.; Roussos, E. +7 more
Radiation belts have been detected in situ at five planets. Only at Earth however has any variability in their intensity been heretofore observed, in indirect response to solar eruptions and high altitude nuclear explosions. The Cassini spacecraft's MIMI/LEMMS instrument has now detected systematic radiation belt variability elsewhere. We report t…
CAWSES November 7-8, 2004, superstorm: Complex solar and interplanetary features in the post-solar maximum phase
Tsurutani, Bruce T.; Echer, Ezequiel; Guarnieri, Fernando L. +1 more
The complex interplanetary structures during 7 to 8 Nov 2004 are analyzed to identify their properties as well as resultant geomagnetic effects and the solar origins. Three fast forward shocks, three directional discontinuities and two reverse waves were detected and analyzed in detail. The three fast forward shocks ``pump'' up the interplanetary …
Large-scale structure of Saturn's E-ring
Morfill, Gregor E.; Horányi, Mihály; Juhász, Antal
Geysers on the recently discovered, geologically active south-polar region of the moon Enceladus are now recognized as the dominant source of material in Saturn's E ring. The ring was traditionally thought to span the region between 3 to 8 R S , where R S is the radius of Saturn. However, new in situ dust measurements indi…
Distribution of the O2 infrared nightglow observed with VIRTIS on board Venus Express
Hueso, R.; Sánchez-Lavega, A.; Erard, S. +5 more
We present characteristics of the statistical horizontal distribution of the O2 infrared nightglow over most of the southern hemisphere observed with the VIRTIS instrument over a period spanning nearly 11 months of low solar activity. We show that the distribution is inhomogeneous with the regions of brightest emission reaching ~3 MegaR…
First identification of mirror mode waves in Venus' magnetosheath?
Zhang, T. L.; Glassmeier, K. -H.; Baumjohann, W. +3 more
In this paper first time observations of mirror mode like structures in Venus' magnetosheath are presented. Using magnetometer data from the Venus Express spacecraft it is shown that in two regions in the Venusian magnetosheath strong compressional waves exist, which propagate nearly perpendicular to the ambient magnetic field. They are most likel…