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Morphology of the ultraviolet Io footprint emission and its control by Io's location
Clarke, John T.; Grodent, Denis; GéRard, Jean-Claude +1 more
A total of 74 images of the ultraviolet footprint of the Io flux tube (IFT) on Jupiter's upper atmosphere made with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope have been analyzed to characterize their location, morphology, and brightness distribution. The observations cover a wide range of central meridian Jovian l…
Enceladus: A significant plasma source for Saturn's magnetosphere
Hill, T. W.; Pontius, D. H.
The Cassini Plasma Spectrometer has reported dramatic perturbations of the magnetospheric plasma flow in a region extending at least 30 satellite radii away from Saturn's small but active icy satellite Enceladus. We interpret these observations here by means of a steady state model of the electrodynamic coupling between Enceladus and Saturn. Neutr…
Interplanetary hydrogen absolute ionization rates: Retrieving the solar wind mass flux latitude and cycle dependence with SWAN/SOHO maps
Bertaux, Jean-Loup; Lallement, Rosine; Schmidt, Walter +4 more
We present results of the total hydrogen ionization rate obtained from the inversion of almost 10 years of full-sky maps of the interplanetary Lyman α background measured by the SWAN instrument on SOHO. Thanks to a new estimate of the absolute calibration of the SWAN instrument and its variation during the 10 years of operation of SOHO, we are abl…
First results from the ionospheric radio occultations of Saturn by the Cassini spacecraft
Anabtawi, Aseel; Barbinis, Elias; Fleischman, Don +9 more
The first set of near-equatorial occultations of the Saturn ionosphere was obtained by the Cassini spacecraft between May and September of 2005. The occultations occurred at near-equatorial latitudes, between 10°N and 10°S, at solar zenith angles from about 84° to 96°. The entry observations correspond to dusk conditions and the exit ones to dawn.…
A statistical comparison of solar wind sources of moderate and intense geomagnetic storms at solar minimum and maximum
Liemohn, Michael W.; Thomsen, Michelle F.; Weygand, James M. +3 more
Superposed epoch analyses of 549 storms are performed to make a comparison of solar wind features of geomagnetic storm events at solar minimum (July 1974 to June 1977; July 1984 to June 1987; July 1994 to June 1997) and solar maximum (January 1979 to December 1981; January 1989 to December 1991; July 1999 to June 2002). In this study, geomagnetic …
Waves and horizontal structures in Titan's thermosphere
Waite, J. H.; Yelle, R. V.; Müller-Wodarg, I. C. F. +1 more
The Ion Neutral Mass Spectrometer (INMS) on board the Cassini spacecraft carried out in situ measurements of neutral gas composition above 1025 km altitude in Titan's atmosphere during its flybys in October 2004 (TA) and April 2005 (T5). Strong perturbations are present in the N2 and CH4 densities which we interpret as vertic…
Characteristics of Jovian morning bright FUV aurora from Hubble Space Telescope/Space Telescope Imaging Spectrograph imaging and spectral observations
Clarke, J. T.; Cowley, S. W. H.; Grodent, D. +3 more
Observation of an exceptionally bright (peaking at ∼1.8 MR) Jovian auroral morning arc was obtained with the Space Telescope Imaging Spectrograph (STIS) on 21 September 1999, both in the imaging and spectral modes. The images of the HST orbit are used to describe the variation of the position of the bright arc, while the time-tagged spectra are ex…
Dependence of flux transfer events on solar wind conditions from 3 years of Cluster observations
Russell, C. T.; Lavraud, B.; Raeder, J. +6 more
We investigate the dependence of Cluster high-latitude magnetopause and low-latitude flank flux transfer events (FTEs) on solar wind conditions using measurements from Cluster FGM and CIS and ACE MFI and SWEPAM between February 2001 and June 2003. We find that there are strong dependences of Cluster FTE occurrence on the IMF Bxgsm, B
Low-frequency wave characteristics in the upstream and downstream regime of the terrestrial bow shock
Dandouras, I.; Glassmeier, K. -H.; RèMe, H. +6 more
Collisionless shocks in space are accompanied by the low-frequency waves of the magnetic field both upstream and downstream of the shock. However, characteristics of these waves in the plasma rest frame are poorly understood, since spatial scale such as wavelength is hardly determined using single or at best two spacecraft observations. Taking adv…
Nature of magnetic fluctuations in Saturn's middle magnetosphere
Russell, C. T.; Dougherty, M. K.; Leisner, J. S. +2 more
The saturnian magnetosphere contains a rich array of plasma wave and MHD wave phenomena. These waves are fed by mass loading in the region of the E ring starting with Enceladus at 3.9 Saturn radii (Rs). In this paper we examine the nature of these waves in what we term to be the middle magnetosphere from just outside the mass loading at Enceladus …