Search Publications
Plume ionosphere of Enceladus as seen by the Cassini ion and neutral mass spectrometer
Luhmann, J. G.; Ip, W. -H.; McNutt, R. L. +4 more
The Cassini spacecraft passed within 168 km of the surface of Enceladus on 14 July 2005 during the E2 flyby and passed closer (50 km) during the E3 encounter on 13 March 2008. During both flybys the ion and neutral mass spectrometer (INMS) detected a plume atmosphere mainly composed of water. During the E3 flyby, the INMS measured an ion mass spec…
Vortex circulation on Venus: Dynamical similarities with terrestrial hurricanes
Piccioni, Giuseppe; Markiewicz, Wojciech J.; Limaye, Sanjay S. +3 more
Some dynamical and morphological similarities exist between the vortex organization of the atmosphere in the northern and southern hemispheres of Venus and the tropical cyclones/hurricanes on Earth. An S-shape feature detected in the center of the vortices on Venus from Pioneer Venus Orbiter and Venus Express observations has also been seen in tro…
Reconstructed and measured total solar irradiance: Is there a secular trend between 1978 and 2003?
Solanki, S. K.; Krivova, N. A.; Wenzler, T.
Total solar irradiance reconstructed between 1978 and 2003 using solar surface magnetic field distributions is compared with three composites of total solar irradiance measurements. A good correspondence is found with the total solar irradiance composite from PMOD/WRC, with no bias between the three cycles. The agreement with the other composites …
Long-lived auroral structures and atmospheric losses through auroral flux tubes on Mars
Barabash, S.; Lundin, R.; Woch, J. +2 more
The ASPERA-3 observations of electron and ion fluxes over the regions dominated by crustal magnetic fields show the existence of long-lived and active aurora-type magnetic flux tubes with a width of 20-150 km. The activity manifests itself by large electron energy fluxes (≥10-4 W/m2) and strong distortions in the upper (350-4…
Is the Martian water table hidden from radar view?
Gurnett, D. A.; Farrell, W. M.; Plaut, J. J. +4 more
Mars may possess a global sub-surface groundwater table as an integral part of its current hydrological system. However, the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) onboard the Mars Express (MEx) spacecraft has yet to make a definitive detection of such a body of liquid water. In this work, we quantify the conditions t…
Stochastic and direct acceleration mechanisms in the Earth's magnetotail
Perri, S.; Zimbardo, G.; Greco, A.
Ion beams with energies of the order of several tens of keV are frequently observed in the Earth's magnetotail. Here we consider two possible acceleration mechanisms, the cross tail electric field E y and the stochastic acceleration due to the electromagnetic fluctuations present in the magnetotail. Electromagnetic perturbations are g…
Methanol on Enceladus
Hodyss, Robert; Goguen, Jay D.; Yung, Yuk L. +4 more
Near infrared spectra of the surface of Enceladus returned by Cassini show the presence of an absorption feature at 3.53 µm, ascribed by Brown et al. (2006) to “short chain organics,” and by Newman et al. (2007) to hydrogen peroxide. We assign this feature tentatively to methanol. Variations in the peak position of the feature suggest that m…
Tracing solar wind plasma entry into the magnetosphere using ion-to-electron temperature ratio
Berchem, J.; Escoubet, C. P.; Dandouras, I. +22 more
When the solar wind Mach number is low, typically such as in magnetic clouds, the physics of the bow shock leads to a downstream ion-to-electron temperature ratio that can be notably lower than usual. We utilize this property to trace solar wind plasma entry into the magnetosphere by use of Cluster measurements in the vicinity of the dusk magnetop…
Plasma environment at Titan's orbit with Titan present and absent
Coates, A. J.; Russell, C. T.; Wei, H. Y. +2 more
To understand the possible large scale influence of Titan on its plasma environment, we study the magnetic fields and plasma measurements, both when Cassini flies close to Titan and when Cassini crosses the moon's orbit far from it. Using 98 Cassini passes from 06/2004 to 12/2008, we examine the plasma environments at the orbit of Titan with the m…
Hydrogen in the extended Venus exosphere
Zhang, T. L.; Volwerk, M.; Bertaux, J. L. +4 more
The nearly absence of water in the atmosphere of Venus is a major difference to the situation at Earth. The actual content of hydrogen in the exosphere is still an open issue, since no in situ measurements are available yet. A different method uses the presence of proton cyclotron waves as an early tracer of ionized planetary hydrogen picked-up by…