Search Publications
Ion sound wave packets at the quasiperpendicular shock front
Krasnoselskikh, V.; Dunlop, M.; Fazakerley, A. +6 more
Electric field measurements from a single spacecraft have been used to study ion-sound turbulence observed within the Earth's bow shock. The observed frequency of the ion-sound waves can be both lower and higher than the local electron cyclotron frequency depending upon the direction of wave propagation in the plasma rest frame. The ion-sound wave…
Structures induced by small moonlets in Saturn's rings: Implications for the Cassini Mission
Seiß, M.; Spahn, F.; Sremčević, M. +1 more
Particle simulations are carried out to study density features caused by small moonlets embedded in a dense planetary ring. The creation of a ``propeller'' like structure is found together with adjacent density wakes. Both features are clear indications for the existence of moonlets in the rings. We confirmed that the propeller scales with the Hil…
The sub-Parker spiral structure of the heliospheric magnetic field
McComas, D. J.; Schwadron, N. A.
Recent studies have shown that the heliospheric magnetic field can be much more radial than the standard Parker spiral in the rarefactions of co-rotation interaction regions (CIRs). This effect can be explained by the motion of open magnetic field foot points at the Sun across the coronal hole boundary. Such motion causes magnetic field lines to b…
Convective plumes and the scarcity of Titan's clouds
Lorenz, Ralph D.; McKay, Christopher P.; Griffith, Caitlin A. +2 more
We show that simple thermodynamic models of convective plumes predict the area fraction of convective plumes (i.e., updrafts) in Titan's atmosphere to be ~12 smaller than on Earth. This result is in agreement with predictions by sophisticated dynamical models and with the relative tropospheric cloud cover, which is only ~1% on Titan. Rainstorms on…
Preliminary results on Saturn's inner plasmasphere as observed by Cassini: Comparison with Voyager
Coates, A. J.; Crary, F.; Johnson, R. E. +12 more
We present an analysis of Saturn's inner plasmasphere as observed by the Cassini Plasma Spectrometer (CAPS) experiment during Cassini's initial entry into Saturn's magnetosphere when the spacecraft was inserted into orbit around Saturn. The ion fluxes are divided into two sub-groups: protons and water group ions. We present the relative amounts of…
Titan's stratospheric zonal wind, temperature, and ethane abundance a year prior to Huygens insertion
Sonnabend, G.; Kostiuk, T.; Murakawa, K. +7 more
Saturn's satellite, Titan, may have stratospheric winds up to ~210 m/s, circling Titan in ~1 terrestrial day compared to its 16-day rotation. Theoretical models explaining such super-rotating winds are not well constrained by observations of Titan or a similar slow rotator, Venus. We report measurements taken in December 2003 of zonal wind near Ti…
New features of electron diffusion regions observed at subsolar magnetic field reconnection sites
Bale, S. D.; Torbert, R. B.; McFadden, J. P. +1 more
Nineteen electron diffusion regions at magnetic field reconnection sites have been found in one hour of Cluster satellite data near the subsolar magnetopause. Investigations on previously unachieved spatial and temporal scales show the following for the first time: direct conversion of magnetic energy to electron energy (The resulting accelerated …
The global plasma environment of Titan as observed by Cassini Plasma Spectrometer during the first two close encounters with Titan
Coates, A. J.; Crary, F.; Johnson, R. E. +17 more
The Cassini spacecraft flew by Titan on October 26, 2004 and December 13, 2004. In both cases it entered the ionosphere of Titan, allowing exploration of its plasma environment. Using observations from the Cassini Plasma Spectrometer (CAPS) and the Cassini magnetometer along the inbound legs of both flybys, we examine Titan's global plasma environ…
Plasma electrons above Saturn's main rings: CAPS observations
Lewis, G. R.; Coates, A. J.; Tokar, R. L. +8 more
We present observations of thermal (~0.6-100eV) electrons observed near Saturn's main rings during Cassini's Saturn Orbit Insertion (SOI) on 1 July 2004. We find that the intensity of electrons is broadly anticorrelated with the ring optical depth at the magnetic footprint of the field line joining the spacecraft to the rings. We see enhancements …
Plasmoid in the high latitude boundary/cusp region observed by Cluster
Balogh, A.; Glassmeier, K. -H.; Zhang, H. +8 more
A plasmoid-like structure without a core magnetic field has been observed by Cluster spacecraft in the high latitude magnetopause region when the interplanetary magnetic field (IMF) is northward and has a dominant duskward component. Bursty electrons and ions are found to be well confined in this plasmoid-like structure. The structure possesses a …