Search Publications
Plasma sheet formation during long period of northward IMF
Phan, Tai D.; Øieroset, Marit; Raeder, Joachim +2 more
We have studied the entry paths of solar wind plasma into the magnetosphere during an extended period of northward IMF using an OpenGGCM MHD simulation of the cold dense plasma sheet (CDPS) event observed on October 23, 2003 by the Cluster spacecraft. We find that high-latitude reconnection occurs tailward of both cusps between the IMF and geomagn…
How typical are atypical current sheets?
Balogh, A.; Zhang, T. L.; Klecker, B. +7 more
Using multi-satellite Cluster magnetic field data, we statistically examined how often an atypical, i.e., non-Harris type, current sheet is formed. We found that a cross-tail current sheet with an off-equatorial current density maximum, indicating bifurcation, is frequently formed in thin current sheets with a half thickness of ~1500 km. The occur…
Titan's ionosphere: Model comparisons with Cassini Ta data
Coates, A. J.; Luhmann, J. G.; Wahlund, J. -E. +13 more
On October 26, 2004, during its first encounter with Titan (Ta), the Cassini Orbiter moved from the dayside to the nightside with a closest approach altitude of 1174 km. In situ measurements of the main part of Titan's ionosphere were made by the Langmuir probe on the Cassini Radio and Plasma Wave Experiment (RPWS), while the Ion and Neutral Mass …
Radial evolution of cross helicity in high-latitude solar wind
Bavassano, B.; Matthaeus, W. H.; Bieber, J. W. +4 more
We employ a turbulence transport theory to explain the high-latitude radial evolution of cross helicity, or Alfvénicity, observed by the Ulysses spacecraft. Evolution is slower than at low latitudes due to weakened shear driving.
Quasi thermal noise spectroscopy in the inner magnetosphere of Saturn with Cassini/RPWS: Electron temperatures and density
Moncuquet, Michel; Meyer-Vernet, Nicole; Lecacheux, Alain +2 more
On 1 July 2004, the Cassini spacecraft performed its Saturn orbit insertion, twice crossing the equatorial plane between the G and F rings. The radio HF receiver observed a peak at the upper-hybrid frequency and weakly banded emissions having well-defined minima at gyroharmonics. We show that through most of the encounter, these emissions do not r…
Equatorial electron density measurements in Saturn's inner magnetosphere
Gurnett, D. A.; Persoon, A. M.; Dougherty, M. K. +4 more
Upper hybrid resonance emissions detected by the Radio and Plasma Wave Science (RPWS) instrument on the Cassini spacecraft are used to obtain electron densities on five equatorial orbits of Saturn at radial distances ranging from 3 to 9 saturnian radii (RS). The electron density profiles for these orbits show a highly repeatable radial …
Periodic intensity variations in global ENA images of Saturn
Krimigis, S. M.; Mitchell, D. G.; Paranicas, C. +4 more
During select time periods in orbit about Saturn, Cassini's Ion and Neutral Camera (INCA) has detected a periodic global ENA signal. Images taken during such periods reveal the presence of a rotating source component in addition to a steady-state component; both components have peak brightness in the midnight sector, when viewed from near dawn. We…
Electron anisotropy constraint in the magnetosheath: Cluster observations
Lavraud, Benoit; Gary, S. Peter; Thomsen, Michelle F. +2 more
The whistler anisotropy instability is driven by the condition T$\perp$e/T$\parallel$e > 1, where the subscript e denotes electrons and the other subscripts denote directions relative to the background magnetic field Bo. Instability growth leads to enhanced field fluctuations which scatter the electrons; theory …
High heat flux on ancient Mars: Evidence from rift flank uplift at Coracis Fossae
Neukum, G.; Hauber, E.; Grott, M. +2 more
We have identified flexural uplift at the flanks of the Coracis Fossae Rift valley. Modeling the topography the elastic thickness is constrained to 10.3-12.5 km, the corresponding mechanical thickness and thermal gradient are 15-19 km and 27-33 K km-1, respectively. The time of rifting is dated by evaluating the crater size-frequency di…
The inner magnetosphere of Saturn: Cassini RPWS cold plasma results from the first encounter
Gurnett, D. A.; Persoon, A. M.; Hospodarsky, G. B. +12 more
We present new results from the inner magnetosphere of Saturn obtained by the Radio and Plasma Wave Science (RPWS) investigation onboard Cassini around the period of the Saturn orbit injection (July 1, 2004). Plasma wave electric field emissions, voltage sweeps by the Langmuir probe (LP) and radio sounder data were used to infer the cold plasma (&…