Search Publications
Magnetopause reconnection impact parameters from multiple spacecraft magnetic field measurements
Wendel, Deirdre E.; Reiff, Patricia H.
We present a novel technique that exploits multiple spacecraft data to determine the impact parameters of the most general form of magnetic reconnection at the magnetopause. The method consists of a superposed epoch of multiple spacecraft magnetometer measurements that yields the instantaneous magnetic spatial gradients near a magnetopause reconne…
Reconnection Hall current system observed in the magnetotail and in the ionosphere
Snekvik, K.; Østgaard, N.; Amm, O. +1 more
On 07 Sep 2001 around 21:40 UT, Cluster was located 19 R E downtail, and observed earthward fast flows and strong perturbations in the dawn-dusk component of the magnetic field (B Y ). The perturbations corresponded to a sheet of tailward field aligned current close to the neutral sheet and another sheet of earthward field…
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 …
Weaker solar wind from the polar coronal holes and the whole Sun
McComas, D. J.; Goldstein, B. E.; Schwadron, N. A. +4 more
Observations of solar wind from both large polar coronal holes (PCHs) during Ulysses' third orbit showed that the fast solar wind was slightly slower, significantly less dense, cooler, and had less mass and momentum flux than during the previous solar minimum (first) orbit. In addition, while much more variable, measurements in the slower, in-ecli…
Hydrocarbon lakes on Titan: Distribution and interaction with a porous regolith
Callahan, P.; Gim, Y.; Stofan, E. +11 more
Synthetic Aperture Radar (SAR) images of Titan's north polar region reveal quasi-circular to complex features which are interpreted to be liquid hydrocarbon lakes. We investigate methane transport in Titan's hydrologic cycle using the global distribution of lake features. As of May 2007, the SAR data set covers ~22% of the surface and indicates mu…
Decrease in heliospheric magnetic flux in this solar minimum: Recent Ulysses magnetic field observations
Smith, Edward J.; Balogh, Andre
The Ulysses spacecraft has traveled from the solar equator at 1.3 and 5.3 AU to above the polar caps at 2.2 AU three times during the last 17 years and has provided measurements of the solar-heliospheric magnetic field. The open magnetic flux, i.e., the radial component, BR, multiplied by the square of the radial distance, r, is indepen…
Titan's inventory of organic surface materials
Kirk, Randolph L.; Lorenz, Ralph D.; Janssen, Michael A. +13 more
Cassini RADAR observations now permit an initial assessment of the inventory of two classes, presumed to be organic, of Titan surface materials: polar lake liquids and equatorial dune sands. Several hundred lakes or seas have been observed, of which dozens are each estimated to contain more hydrocarbon liquid than the entire known oil and gas rese…
Compositional stratigraphy of clay-bearing layered deposits at Mawrth Vallis, Mars
Mustard, J. F.; Wray, J. J.; Ehlmann, B. L. +2 more
Phyllosilicates have previously been detected in layered outcrops in and around the Martian outflow channel Mawrth Vallis. CRISM spectra of these outcrops exhibit features diagnostic of kaolinite, montmorillonite, and Fe/Mg-rich smectites, along with crystalline ferric oxide minerals such as hematite. These minerals occur in distinct stratigraphic…
Variable winds on Venus mapped in three dimensions
Baines, K. H.; Hueso, R.; Sánchez-Lavega, A. +9 more
We present zonal and meridional wind measurements at three altitude levels within the cloud layers of Venus from cloud tracking using images taken with the VIRTIS instrument on board Venus Express. At low latitudes, zonal winds in the Southern hemisphere are nearly constant with latitude with westward velocities of 105 ms-1 at cloud-top…
Energetic ion precipitation at Titan
Krimigis, S. M.; Waite, J. H.; Cravens, T. E. +3 more
Energetic protons and oxygen ions have been observed in Saturn's outer magnetosphere and can precipitate into Titan's atmosphere where they deposit energy, ionize, and drive ionospheric chemistry. Ion production rates caused by this precipitation are calculated using fluxes of incident 27 keV to 4 MeV protons measured by the Cassini MIMI instrumen…