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Observations of molecular oxygen ions in Saturn's inner magnetosphere
Johnson, Robert E.; Smith, H. Todd; Martens, Hilary R. +2 more
We present an analysis of molecular oxygen ion (O2 +) abundance in Saturn's inner magnetosphere based on observations made with the Cassini Plasma Spectrometer (CAPS). Using data summed over 23 orbits, we resolve and isolate O2 + counts from the tail of the water group ion mass distribution (W+
Thermal electron periodicities at 20RS in Saturn's magnetosphere
André, N.; Lewis, G. R.; Coates, A. J. +6 more
Cassini fields and particles observations show clear evidence of periodic phenomena in Saturn's magnetosphere. Periodicities have been observed in kilometric radio emissions, total electron density (in the inner magnetosphere), magnetic fields, and energetic particles (in the outer magnetosphere). In this letter the first analysis of periodicities…
Near-surface heating on Enceladus and the south polar thermal anomaly
Nimmo, F.; Roberts, J. H.
Strike-slip motion is predicted to be a consequence of diurnal tidal stresses in most satellites of the outer solar system. Such motion can lead to near-surface heating through friction or viscous dissipation. Here we discuss the effect of near-surface shear heating on convection in the underlying ice shells of icy satellites. We present models of…
Electron trapping around a magnetic null
Escoubet, C. P.; Dandouras, I.; Glassmeier, K. -H. +18 more
Magnetic reconnection is an important process in astrophysical, space and laboratory plasmas. The magnetic null pair structure is theoretically suggested to be a crucial feature of the three-dimensional magnetic reconnection. The physics around the null pair, however, has not been explored in combination with the magnetic field configuration deduc…
Confirmation and utilization of the ``production function'' size-frequency distributions of Martian impact craters
Neukum, Gerhard; Werner, Stephanie; Hartmann, William K.
On any planetary surface, impacts of interplanetary bodies create an initial (or ``production function'') size-frequency distribution (SFD) of impact craters. Recent questions have been raised about whether this size distribution can be reliably detected, especially at small sizes. In a test area, we confirm an excellent fit to the distribution we…
Behavior of current sheets at directional magnetic discontinuities in the solar wind at 0.72 AU
Russell, C. T.; Zhang, T. L.; Glassmeier, K. -H. +10 more
Venus Express interplanetary magnetic field measurements have been examined for magnetic ``holes,'' accompanied by magnetic field directional changes. We examine both the thickness of the current sheet and the depth of the magnetic field depression. We find the thickness of the current sheet is not correlated with the depth of the field depression…
Implications from Ithaca Chasma for the thermal and orbital history of Tethys
Nimmo, F.; Chen, E. M. A.
Flexural modeling of Ithaca Chasma on Tethys suggests that the elastic thickness and the surface heat flux were 5-7 km and 18-30 mW/m2 respectively, when the feature formed (~4 Gyr B.P.). Tidal heating is a plausible heat source, suggesting that Tethys' eccentricity was higher in the past. Depending on Tethys' internal structure, eccent…
Structure of Titan's low altitude ionized layer from the Relaxation Probe onboard HUYGENS
Berthelier, J. J.; Rodrigo, R.; López-Moreno, J. J. +14 more
Some of the secrets of the atmosphere of Titan have been unveiled by the Huygens Probe. The Permitivity Wave and Altimetry system detected a hidden ionosphere much below the main ionosphere, that lies between 600 and 2000 km. Theoretical models predicted a low altitude ionosphere produced by cosmic rays that, contrary to magnetospheric particles a…
Modulated reconnection rate and energy conversion at the magnetopause under steady IMF conditions
Dandouras, I.; Buchert, S.; Vaivads, A. +4 more
We use the multi-spacecraft mission Cluster to make observational estimates of the local energy conversion across the dayside high-latitude magnetopause. The energy conversion is estimated during eleven complete magnetopause crossings under steady south-dawnward interplanetary magnetic field (IMF). We describe a new method to determine the reconne…
Lunar degree 2 potential Love number determination from satellite tracking data
Matsumoto, K.; Goossens, S.
The lunar potential Love number k 2 has been determined using available satellite tracking data coming from the Lunar Orbiters I-V, the Apollo 15 and 16 subsatellites, Clementine and Lunar Prospector. Some SMART-1 spacecraft tracking data are also included. A previous determination using spacecraft data reported k 2 = 0.026 +…