References of "Grodent, Denis"
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See detailSaturn's polar auroral emissions
Radioti, Aikaterini ULg; Gérard, Jean-Claude ULg; Grodent, Denis ULg et al

Conference (2010)

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See detail"Giant Planets Aurorae" - Europlanet RI Science Case in the Working Packages
Rucker, M Scherf H O; Blanc, M.; André, N. et al

Conference (2010)

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See detailVariation of Saturn's UV aurora with SKR phase
Nichols, J. D.; Cecconi, B.; Clarke, J. T. et al

in Geophysical Research Letters (2010), 37

It is well known that a wide range of kronian magnetospheric phenomena, including the Saturn kilometric radiation (SKR), exhibit oscillations near the planetary rotation period. However, although the SKR ... [more ▼]

It is well known that a wide range of kronian magnetospheric phenomena, including the Saturn kilometric radiation (SKR), exhibit oscillations near the planetary rotation period. However, although the SKR is believed to be generated by unstable auroral electrons, no connection has been established to date between diurnal SKR modulations and UV auroral power. We use an empirical SKR phase determined from Cassini observations to order the 'quiet time' total emitted UV auroral power as observed by the Hubble Space Telescope in programs during the interval 2005-2009. Our results indicate that both the northern and southern UV powers are dependent on SKR phase, varying diurnally by factors of similar to 3. We also show that the UV variation originates principally from the morning half of the oval, consistent with previous observations of the SKR sources. Citation: Nichols, J. D., B. Cecconi, J. T. Clarke, S. W. H. Cowley, J.-C. Gerard, A. Grocott, D. Grodent, L. Lamy, and P. Zarka (2010), Variation of Saturn's UV aurora with SKR phase, Geophys. Res. Lett., 37, L15102, doi: 10.1029/2010GL044057. [less ▲]

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See detailLocation and spatial shape of electron beams in Io's wake
Jacobsen, S.; Saur, J.; Neubauer, F. M. et al

in Journal of Geophysical Research. Solid Earth (2010), 115

The Galileo spacecraft observed energetic field-aligned electron beams very close to Io during several flybys. We apply a three-dimensional magnetohydrodynamic (MHD) model of the far-field Io-Jupiter ... [more ▼]

The Galileo spacecraft observed energetic field-aligned electron beams very close to Io during several flybys. We apply a three-dimensional magnetohydrodynamic (MHD) model of the far-field Io-Jupiter interaction to simulate for the first time the location and spatial shape of field-aligned electron beams. Io continuously generates MHD waves by disturbing the Jovian magnetoplasm. Currents carried by Alfven waves propagate predominantly along the magnetic field lines. As the number of charge carriers decreases along the travel path, electrons are accelerated toward Jupiter. These energetic electrons precipitate into the Jovian ionosphere, visible as prominent Io footprint emission. Electrons are also accelerated toward Io and form the equatorial beams observed by the Galileo spacecraft. Unlike the beam formation, the position and spatial structure of these beams have not been addressed in detail before. We use a 3-D MHD model with initial conditions corresponding to the individual Galileo flyby and determine the spatial morphology of the beams in Io's orbital plane. Our results for the beam locations are in good agreement with the Galileo Energetic Particle Detector observations. We find that the ratio of the one-way travel time of the Alfven wave from Io to Jupiter and the convection time of the plasma past the obstacle controls the location of the beam. This leads to the conclusion that at other satellites with other plasma environments, the electrons might not be close to the satellite but can be shifted significantly downstream along its plasma wake. Thus, the future search for electron beams near a satellite should be further extended to the wake region. [less ▲]

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See detailThe Spatial Morphology of Equatorial Electron Beams Near Io
Jacobsen, S.; Saur, J. S.; Neubauer, F. M. et al

Conference (2009, December 14)

The Galileo spacecraft observed energetic field-aligned electron beams very close to Io during several flybys. We apply a three-dimensional magnetohydrodynamic (MHD) model of the far-field Io-Jupiter ... [more ▼]

The Galileo spacecraft observed energetic field-aligned electron beams very close to Io during several flybys. We apply a three-dimensional magnetohydrodynamic (MHD) model of the far-field Io-Jupiter interaction to simulate for the first time the location and spatial shape of field-aligned electron beams. Io continuously generates MHD waves by disturbing the Jovian magnetoplasma. Currents carried by Alfvén waves propagate predominantly along the magnetic field lines. As the number of charge carriers decreases along the travelpath, electrons are accelerated towards Jupiter. These energetic electrons precipitate into the Jovian ionosphere, visible as prominent Io footprint (IFP) emission. Electrons are also accelerated towards Io and form the equatorial beams observed by the Galileo spacecraft. Unlike the beam formation, the position and spatial structure of these beams has not been addressed in detail before. We use a 3D MHD model with initial conditions corresponding to the individual Galileo flyby and determine the spatial morphology of the beams in Io's orbital plane. Our results are in good agreement with the Galileo observations. We find that the ratio of the one-way traveltime of the Alfvén wave from Io to Jupiter and the convection time of the plasma past the obstacle controls the location of the beams. This leads to the conclusion that at other satellites with other plasma environments, e.g. Ganymede, Callisto, Europa and Enceladus, the electron beams might not be close to the satellite, but can be shifted significantly downstream along its plasma wake. Thus, the future search for field-aligned electron populations near a satellite should be further extended to the wake region. [less ▲]

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See detailSaturn Auroral Movies from Cassini UVIS
Pryor, W. R.; Stewart, I.; Esposito, L. W. et al

in American Geophysical Union, Fall Meeting 2009 (2009, December 01)

Cassini's Ultraviolet Imaging Spectrograph (UVIS) continues to obtain Saturn auroral data. Two long slit spectral channels are used to obtain EUV data from 56.3-118.2 nm and FUV data from 111.5-191.3 nm ... [more ▼]

Cassini's Ultraviolet Imaging Spectrograph (UVIS) continues to obtain Saturn auroral data. Two long slit spectral channels are used to obtain EUV data from 56.3-118.2 nm and FUV data from 111.5-191.3 nm. 64 spatial pixels along each slit are combined with slit motion to construct spectral images of Saturn. Auroral emissions are seen from electron-excited molecular and atomic hydrogen. In 2007-2009 UVIS obtained data with the spacecraft well out of Saturn's ring plane, permitting UVIS to obtain a number of short movies of the rotating auroral structures. Selected movies will be presented with geometric overlays and in polar projections. In some movies a cusp-like feature is present near noon inside the oval. One movie from 2008 day 201 shows parallel linear features on the day side almost at right angles to the main auroral oval that appear, then lengthen, separate in the middle, and then fade away. Other movies show similar cusp-related structures that resemble the letter "Q" where a dynamical feature at right angles to the oval moves away from the cusp region. The 2008 day 201 movie also shows one bright "polar flare" inside the oval with a spectrally distinct signature indicating the presence of higher energy electrons. A few of the most recent images were obtained at sufficiently close range that 2 spacecraft slews were needed to completely cover the oval. These images provide almost 100 pixels of information across the oval and clearly show multiple arcs of emission on the main oval and scattered emissions inside the oval. Several frames show emissions associated with the footprint of the Enceladus field line. We will discuss these features, their locations, and possible interpretations. [less ▲]

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See detailRecurrent energization of plasma in the midnight-to-dawn quadrant of Saturn's magnetosphere, and its relationship to auroral UV and radio emissions
Mitchell, D. G.; Krimigis, S. M.; Paranicas, C. et al

in Planetary and Space Science (2009), 57

We demonstrate that under some magnetospheric conditions protons and oxygen ions are accelerated once per Saturn magnetosphere rotation, at a preferred local time between midnight and dawn. Although ... [more ▼]

We demonstrate that under some magnetospheric conditions protons and oxygen ions are accelerated once per Saturn magnetosphere rotation, at a preferred local time between midnight and dawn. Although enhancements in energetic neutral atom (ENA) emission may in general occur at any local time and at any time in a Saturn rotation, those enhancements that exhibit a recurrence at a period very close to Saturn's rotation period usually recur in the same magnetospheric location. We suggest that these events result from current sheet acceleration in the 15-20 Rs range, probably associated with reconnection and plasmoid formation in Saturn's magnetotail. Simultaneous auroral observations by the Hubble Space Telescope (HST) and the Cassini Ultraviolet Imaging Spectrometer (UVIS) suggest a close correlation between these dynamical magnetospheric events and dawn-side transient auroral brightenings. Likewise, many of the recurrent ENA enhancements coincide closely with bursts of Saturn kilometric radiation, again pointing to possible linkage with high latitude auroral processes. We argue that the rotating azimuthal asymmetry of the ring current pressure revealed in the ENA images creates an associated rotating field aligned current system linking to the ionosphere and driving the correlated auroral processes. [less ▲]

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See detailThe very busy auroral footprint of Ganymede
Grodent, Denis ULg; Bonfond, Bertrand ULg; Radioti, Aikaterini ULg et al

Conference (2009, September 13)

Detailed reference viewed: 1 (0 ULg)
See detailJupiter's ultraviolet polar auroral emissions
Coumans, Valérie ULg; Bonfond, Bertrand ULg; Grodent, Denis ULg et al

Conference (2009, September)

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See detailRecurrent Energization of Plasma in the Midnight-to-Dawn Quadrant of Saturn's Magnetosphere, and its Relationship to Auroral UV and Radio Emissions
Mitchell, D.; Krimigis, S.; Paranicas, C. et al

Poster (2009, August 11)

Detailed reference viewed: 3 (1 ULg)
See detailHST observations of Europa's atmospheric UV emission
Saur, J.; Feldman, P. D.; Strobel, D. F. et al

Conference (2009, July 27)

Detailed reference viewed: 7 (2 ULg)
See detailDoes Saturn's UV aurora vary with SKR phase?
Nichols, J. D.; Cowley, S. W. H.; Clarke, J. T. et al

Conference (2009, July 27)

Detailed reference viewed: 2 (1 ULg)
See detailSaturn's equinoctial auroras
Nichols, J. D.; Gérard, Jean-Claude ULg; Grodent, Denis ULg et al

Conference (2009, July 27)

Detailed reference viewed: 6 (2 ULg)
See detailThe morphology of equatorial electron beams at Io
Jacobsen, S.; Saur, J.; Neubauer, F. M. et al

Conference (2009, July 27)

Detailed reference viewed: 5 (1 ULg)
See detailSaturn Auroral Images and Movies from Cassini UVIS
Pryor, W. R.; Grodent, Denis ULg; Gérard, Jean-Claude ULg

Conference (2009, July 27)

Detailed reference viewed: 5 (2 ULg)
See detailObservations of jovian polar auroral filaments
Nichols; Clarke; Gérard et al

Poster (2009, July 27)

Detailed reference viewed: 2 (0 ULg)