Search Publications
Foreshock cavities and internal foreshock boundaries
Schwartz, Steven J.; Billingham, Laurence; Wilber, Mark
We present two case studies of cluster encounters with foreshock cavities. For one event, we are able, for the first time, to accurately relate the observation of a foreshock cavity to the measured position of the bow shock. This allows us to compute the shock angle, a vital parameter in models of foreshock cavity formation, with greater confidenc…
Magnetic field modulated dust streams from Jupiter in interplanetary space
Flandes, Alberto; Krüger, Harald; Hamilton, Douglas P. +3 more
High speed dust streams emanating from near Jupiter were first discovered by the Ulysses spacecraft in 1992. Since then the phenomenon has been re-observed by Galileo in 1995, Cassini in 2000, and Ulysses in 2004. The dust grains are expected to be charged to a potential of ∼5 V, which is sufficient to allow the planet's magnetic field to accelera…
Multilayer simulations for accurate geological interpretations of SHARAD radargrams
Franco, M.; Spagnuolo, M. G.; Grings, F. +3 more
SHARAD (SHAllow RADar) is a nadir-looking Synthetic Aperture Ground Penetrating Radar on board NASA's 2005 Mars Reconnaissance Orbiter. There are three main characteristics that define the performance of this instrument: ground penetration (due to the operational frequency, the observed echoes can be related to reflections from surface or subsurfa…
Study of inertial kinetic Alfven waves around cusp region
Agarwal, P.; Varma, P.; Tiwari, M. S.
The effect of electron inertia on kinetic Alfven wave has been studied. The expressions for the dispersion relation, growth/damping rate and growth/damping length of the inertial kinetic Alfven wave (IKAW) are derived using the kinetic approach in cusp region. The Vlasov-kinetic theory has been adopted to evaluate the dispersion relation, growth/d…
On the effect of line current width and relative position on the multi-spacecraft curlometer technique
Fazakerley, A. N.; Lester, M.; Owen, C. J. +2 more
The response of the multi-spacecraft curlometer technique to variations in the size and relative position of infinitely long line currents with radially varying current density is systematically investigated for spacecraft in a regular tetrahedral formation. It is shown that, for line currents with a width less than the spacecraft separation, ther…
Multi-spacecraft investigation of space turbulence: Lessons from Cluster and input to the Cross-Scale mission
Belmont, Gérard; Rezeau, Laurence; Sahraoui, Fouad +9 more
Investigating space plasma turbulence from single-point measurements is known to be characterized by unavoidable ambiguities in disentangling temporal and spatial variations. Solving this problem has been one of the major goals of the Cluster mission. For that purpose multipoint measurements techniques, such as the k-filtering, have been developed…
Observations of dawn-dusk aligned polar cap aurora during the substorms of January 21, 2005
Tsurutani, B. T.; Du, A. M.; Sun, W. +2 more
A new type of polar cap aurora, dawn-dusk aligned polar cap aurora (DDAPCA), was detected during the exceptionally intense January 21, 2005 substorm (AEmax=3504 nT). The DDAPCA was located at very high latitude (>85° MLAT) in the polar cap region. As the interplanetary magnetic field (IMF) GSM By component rotated from a positive to …
Harmakhis Vallis Source Region, Mars: Insights into the recent geothermal history based on geological mapping
Komatsu, Goro; Marinangeli, Lucia; Glamoclija, Mihaela
The mapped area of Harmakhis Vallis, at the eastern Hellas Planitia region (35°30-42°50'S; 91°00-97°30'E), covers the surface area of about 212,000 km 2. The region displays an enhanced modification of the initial topography formed by the Hellas impact. The long and complex history of degradation and alteration involves mass-wasting pro…
Motion of blocks on the surface of Phobos: New constraints for the formation of grooves
Hamelin, Michel
Although grooves are common on asteroids, on Phobos the grooves have been the subject of various formation hypotheses for two reasons: the fact that Phobos is orbiting around Mars close to the Roche limit, implies an unusual gravity environment as well as the presence of the huge crater impact, Stickney, which seems to be related at least to a fam…
Interferometric millimeter observations of water vapor on Mars and comparison with Mars Express measurements
Montmessin, Franck; Lellouch, Emmanuel; Fouchet, Thierry +3 more
We present interferometric mapping of the 225.9-GHz HDO and 203.4-GHz H2O lines on Mars obtained with the IRAM Plateau de Bure facility (PdBI). The observations were performed during martian year 28 (MY28), at Ls=320.3° for the HDO line, and at Ls=324.3° for the H2O line. The HDO line is detected at the …