Search Publications
Mode conversion between Alfvén and slow waves observed in the magnetotail by THEMIS
Zhang, T. L.; Glassmeier, K. -H.; Nakamura, R. +6 more
We present the direct spacecraft observations of wave mode conversion in the magnetotail for the first time. On February 28, 2008, the satellites P4 and P3 of THEMIS observe wave signals with a period of about 100 s in the magnetotail at about 11 RE. At the same time, geomagnetic activity is very quiet and there are no wave signals obse…
Simulating the time-dependent response of Titan's upper atmosphere to periods of magnetospheric forcing
Westlake, Joseph; Waite, J. Hunter, Jr.; Bell, Jared M.
We demonstrate that a simulation of Titan's upper atmosphere can exhibit significant short-term temperature variations when exposed to globally averaged plasma heating rates over periods of 8 Earth days (0.5 Titan days). Temperature enhancements can range from 16 K when exposed to column-integrated, orbit-averaged heating rates of 2.5 × 108
Long term time variations of the suprathermal ions in Saturn's magnetosphere
Krimigis, S. M.; Mitchell, D. G.; Hamilton, D. C. +1 more
We use the Charge-Energy-Mass Spectrometer (CHEMS) on Cassini to study long-term time variations of the suprathermal (E/Q = 27-220 keV/e) ions in Saturn's equatorial ring current (Latitude = -10° to 10°, dipole L = 7-16) from the end of 2004 to the end of 2010. We identify five equatorial time periods, which vary in length from 124 to 282 days, an…
Charged particle acceleration by intermittent electromagnetic turbulence
Petrukovich, A. A.; Zelenyi, L. M.; Artemyev, A. V. +2 more
We studied the role of intermittency in the process of acceleration and transport of charged particles by electromagnetic turbulence. We propose a simple model of electromagnetic turbulence with a variable level of intermittency. The magnetic field is described as a superposition of an ensemble of magnetostatic plane waves and of spatially localiz…
The rotation of the plasmapause-like boundary at high latitudes in Saturn's magnetosphere and its relation to the eccentric rotation of the northern and southern auroral ovals
Gurnett, D. A.; Persoon, A. M.; Kurth, W. S. +4 more
Here we present a study of the rotation of the plasmapause-like density boundary discovered by the Cassini spacecraft at high latitudes in the Saturnian magnetosphere, and compare the results with previously published studies of high-latitude magnetic field perturbations and the eccentric rotation of the auroral ovals. Near the planet the density …
Fluid simulations of mirror constraints on proton temperature anisotropy in solar wind turbulence
Passot, T.; Sulem, P. L.; Laveder, D. +1 more
Non-resonant ion perpendicular heating by low-frequency kinetic Alfvén wave turbulence, together with the constraining effect of the mirror instability on the developing temperature anisotropy observed in the solar wind, are simulated for the first time in a self-consistent way using a fluid model retaining low-frequency kinetic effects. This mode…
Day-night asymmetries of low-energy electrons in Saturn's inner magnetosphere
Coates, A. J.; Crary, F.; Burch, J. L. +2 more
We examine the day-night asymmetry of near-equatorial low energy (12-100 eV) electron fluxes measured by Cassini from July 1, 2004 through April 1, 2010. This energy range is also known to be associated with interchange injections. The electrons are separated into field-aligned (0° to 20° and 160° to 180°) pitch angles and trapped (70° to 110°) pi…
Comparison of Titan's north polar lakes with terrestrial analogs
Byrne, Shane; Sharma, Priyanka
The discovery of hydrocarbon lakes in the polar regions of Titan offers a unique opportunity to compare terrestrial lakes with those in an extraterrestrial setting. We selected 114 terrestrial lakes formed by different processes as analogs for comparison with the 190 Titanian lakes that we had mapped in our previous study. Using the Shuttle Radar …
Vaduz, an unusual fresh crater on Mars: Evidence for impact into a recent ice-rich mantle
Head, James W.; Kadish, Seth J.; Schaefer, Ethan I.
A fresh, 1.85 km diameter impact crater in the midlatitudes of Mars (38°N) named Vaduz exhibits distinctive crater-related geological subunits (facies) extending up to ∼15 radii from the rim crest and perched >10 m above the adjacent plains. Knobby terrain fringing and underlying the facies is interpreted as degraded thermal contraction crack p…
SAID/SAPS-related VLF waves and the outer radiation belt boundary
Mishin, Evgeny; Santolik, Ondrej; Albert, Jay
We explore Cluster and CRRES observations of plasmaspheric broadband hiss-like VLF emissions related with subauroral ion drifts/polarization streams (SAID/SAPS) to numerically simulate losses of energetic outer zone electrons due to wave-particle interactions. These emissions represent a distinctive subset of substorm/storm-related VLF activity in…