Search Publications
Electron properties of high-speed solar wind from polar coronal holes obtained by Ulysses thermal noise spectroscopy: Not so dense, not so hot
McComas, D. J.; Issautier, K.; MacDowall, R. J. +4 more
We present radio observations of Ulysses' third fast latitude scan near the 2007 solar activity minimum of cycle 23. We deduce in situ measurements of the electron density and temperature using the method of quasi-thermal noise spectroscopy. We study the large-scale properties of the fast solar wind coming from polar coronal holes and compare our …
Cassini detection of water-group pick-up ions in the Enceladus torus
Thomsen, M. F.; Wilson, R. J.; Tokar, R. L. +8 more
This study reports direct detection by the Cassini plasma spectrometer of freshly-produced water-group pick-up ions within the proposed Enceladus torus, a radially narrow toroidal region surrounding Saturn that contains a high density of water-group neutrals. This torus is produced by the icy plumes observed near the south pole of Enceladus. The i…
Auroral polar dawn spots: Signatures of internally driven reconnection processes at Jupiter's magnetotail
Bonfond, B.; Clarke, J. T.; Gérard, J. -C. +2 more
We report the presence of polar spots located in the dawn auroral region, based on the HST ACS 2007 campaign. We study the location of these features in the equatorial plane as well as their time scales and periodicities, based on a comprehensive series of images taken between February 21 and June 11, 2007. It is shown that the majority of polar d…
Magnetic double gradient mechanism for flapping oscillations of a current sheet
Semenov, V. S.; Erkaev, N. V.; Biernat, H. K.
A new kind of magnetohydrodynamic waves are analyzed for a current sheet in a presence of a small normal magnetic field component varying along the sheet. As a background, two simplified models of a current sheet are considered with a uniform and nonuniform current distributions in the current sheet. On a basis of these two models, the flapping-ty…
Geology of Shackleton Crater and the south pole of the Moon
Josset, Jean-Luc; Spudis, Paul D.; Bussey, Ben +2 more
Using new SMART-1 AMIE images and Arecibo and Goldstone high resolution radar images of the Moon, we investigate the geological relations of the south pole, including the 20 km-diameter crater Shackleton. The south pole is located inside the topographic rim of the South Pole-Aitken (SPA) basin, the largest and oldest impact crater on the Moon and …
First upstream proton cyclotron wave observations at Venus
Russell, C. T.; Wei, H. Y.; Zhang, T. L. +3 more
The escape of particles from planetary atmospheres, especially hydrogen, is an important key towards understanding the atmospheric composition and evolution over the lifetime of the solar system. For an unmagnetized planet such as Venus or Mars when the neutral exosphere extends into the flowing solar wind plasma, loss of pick-up ions upstream of …
Periodic tilting of Saturn's plasma sheet
Krimigis, S. M.; Mitchell, D. G.; Roelof, E. C. +2 more
From the vantage of the dawn sector, the INCA instrument on Cassini imaged neutral hydrogen atoms (20-50 keV) emitted from the center of the Saturn's plasma sheet for five days during late 2004. Points along the center of the plasma sheet were found from contoured images projected onto the noon-midnight plane; points within 20 RS of Sat…
Titan's influence on Saturnian substorm occurrence
Russell, C. T.; Wei, H. Y.; Dougherty, M. K. +2 more
Substorms play an important role in the energization and transport of plasmas in planetary magnetospheres, including the shedding of the mass added by moons in the case of Jupiter and Saturn. Mass shedding occurs through rapid reconnection in the near tail resulting in dipolarization on the magnetospheric side of the reconnection point and plasmoi…
Titan airglow spectra from the Cassini Ultraviolet Imaging Spectrograph: FUV disk analysis
Stewart, Ian; Gustin, Jacques; Ajello, Joseph M. +7 more
We present a spectral analysis of the far ultraviolet (FUV: 1150-1900 Å) disk airglow observations of Titan's atmosphere by the Cassini Ultraviolet Imaging Spectrograph (UVIS). The FUV spectrum consists of emissions from the Lyman-Birge-Hopfield (LBH) band system of N2 excited by photoelectrons (a 1Πg → X 1Σg +), N I multiplets from solar photodis…
Plasma convection in Saturn's outer magnetosphere determined from ions detected by the Cassini INCA experiment
Krimigis, S. M.; Mitchell, D. G.; Carbary, J. F. +2 more
The Ion and Neutral Camera (INCA), one of three sensors comprising the Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft, measures intensities of hydrogen and oxygen ions and neutral atoms in the Saturnian magnetosphere. The measured intensity spectrum and anisotropy of hot hydrogen and oxygen ions may be used to deduce the spectr…