Search Publications
A new semiempirical model of the peak electron density of the Martian ionosphere
Withers, Paul; Mendillo, Michael; Morgan, David +2 more
of the ionosphere of Mars have now reached a sufficient number to begin discussions on how best to create an empirically based model of its global morphology. Here we use nearly 113,000 values of maximum electron density (Nmax) obtained from 2005 to 2012 by the Mars Advanced Radar for Subsurface and Ionospheric Sounding on board the Mar…
Storm-induced energization of radiation belt electrons: Effect of wave obliquity
Zelenyi, L. M.; Krasnoselskikh, V.; Artemyev, A. V. +2 more
New Cluster statistics allow us to determine for the first time the variations of both the obliquity and intensity of lower-band chorus waves as functions of latitude and geomagnetic activity near L∼5. The portion of wave power in very oblique waves decreases during highly disturbed periods, consistent with increased Landau damping by inward-penet…
Phobos 2/ASPERA data revisited: Planetary ion escape rate from Mars near the 1989 solar maximum
Barabash, Stas; Lundin, Rickard; Nilsson, Hans +4 more
Insights about the near-Mars space environment from Mars Express observations have motivated a revisit of the Phobos 2/ASPERA ion data from 1989. We have expanded the analysis to now include all usable heavy ion (O+, O2+, CO2+) measurements from the circular orbits of Phobos 2. Phobos 2/ASPERA ion fluxes in the Martian tail are compared…
An unidentified emission in Titan's upper atmosphere
López-Puertas, M.; D'Aversa, E.; García-Comas, M. +4 more
We have analyzed limb daytime observations of Titan's upper atmosphere at 3.3 µm, acquired by the visual-infrared mapping spectrometer (VIMS) on Cassini. They were previously studied by García-Comas et al. (2011) to derive CH4 densities. Here, we report an unidentified emission peaking around 3.28 µm, hidden under the methan…
Observation of multiple sub-cavities adjacent to single separatrix
Daly, P. W.; Zhang, Tielong; Kronberg, E. A. +7 more
investigate a direct south-north crossing of a reconnection ion diffusion region in the magnetotail. During this crossing, multiple electron density dips with a further density decrease within the cavity, called sub-cavities, adjacent to the northern separatrix are observed. The correlation between electron density sub-cavities and strong electric…
The multiple spots of the Ganymede auroral footprint
Bagenal, F.; Bonfond, B.; Clarke, J. T. +5 more
The interaction between the moons and the magnetosphere of giant planets sometimes gives rise to auroral signatures in the planetary ionosphere, called the satellite footprints. So far, footprints have been detected for Io, Europa, Ganymede, and Enceladus. These footprints are usually seen as single spots. However, the Io footprint, the brightest …
Extreme densities in Titan's ionosphere during the T85 magnetosheath encounter
Dougherty, M. K.; Roussos, E.; Garnier, P. +10 more
We present Cassini Langmuir probe measurements of the highest electron number densities ever reported from the ionosphere of Titan. The measured density reached 4310 cm-3 during the T85 Titan flyby. This is at least 500 cm-3 higher than ever observed before and at least 50% above the average density for similar solar zenith a…
Determining olivine composition of basaltic dunes in Gale Crater, Mars, from orbit: Awaiting ground truth from Curiosity
Christensen, Philip R.; Lane, Melissa D.
successful landing of the Mars Science Laboratory Curiosity rover in Gale Crater, Mars, presents a rare opportunity for validation of a spectral index developed for determining olivine chemistry from orbital midinfrared remote-sensing data. Here, a spectral index is developed using laboratory emissivity data of 13 synthetic Mg-Fe olivines. Utilizi…
Dependence of O+ escape rate from the Venusian upper atmosphere on IMF directions
Fedorov, A.; Barabash, S.; Futaana, Y. +5 more
investigate the dependence of the O+ escape rate on the upstream interplanetary magnetic field (IMF) direction by using data from the Analyser of Space Plasma and Energetic Atoms (ASPERA-4) instrument and the magnetometer (MAG) onboard Venus Express. We consider two cases, namely the perpendicular IMF case (167 events) and the parallel …
Resonant diffusion of energetic electrons by narrowband Z mode waves in Saturn's inner magnetosphere
Ni, Binbin; Gu, Xudong; Ye, Sheng-Yi +1 more
<title type="main">Abstract<p label="1">Banded emissions near 5 and 20 kHz are observed by the Cassini Radio and Plasma Wave Science (RPWS) instrument and are identified as Z mode waves in the regions where the plasma frequency is below the electron gyrofrequency. Using wave parameters derived from Gaussian fits to the measured power s…