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See detailJupiter’s magnetopause: A search for wave and reconnection signatures
Bonfond, Bertrand ULiege; Kivelson, M. G.; Khurana, K. K. et al

Conference (2014, September 12)

Surface waves and magnetic reconnection are two key processes taking place at the planetary magnetopause. They allow the coupling, through energy (and particle) transfer, of the interplanetary medium and ... [more ▼]

Surface waves and magnetic reconnection are two key processes taking place at the planetary magnetopause. They allow the coupling, through energy (and particle) transfer, of the interplanetary medium and the magnetosphere. The relative importance of large scale Dungey reconnection and viscous interaction (including small-scale intermittent reconnection associated with Kelvin-Helmholtz vortices) are expected to be different at Jupiter compared to the Earth’s case. Such differences would be due to the combination of a) a weaker solar wind pressure and Alfvén velocity as the distance to the Sun increases, b) a high-β plasma sheet, originating from Io’s outgassing, which inflates the Jovian magnetosphere, c) the rapid rotation of the planet relative to its size (e.g. Desroche et al. 2012). Here we analyse the signatures of wave activity and reconnection on the magnetopause of Jupiter, based on magnetic field and energetic particle measurements from the successive spacecraft that explored the Jovian system. Up to now, 7 spacecraft equipped with a magnetometer have crossed the Jovian magnetopause: Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Ulysses, Galileo and Cassini. We make use of several normal direction finding techniques, such as the Minimum Variance Analysis, in order to identify waves and Kelvin-Helmholtz vortices. As far as the reconnection is concerned, small scale signatures of flux-tube events (FTEs) had been identified by Walker and Russell (1985), based on a limited data-set from the Pioneers’ and Voyagers’ fly-bys. Here we will extend this search to the extensive dataset from all the missions that explored Jupiter’s system. [less ▲]

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See detailJupiter's magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits
Connerney, J. E. P.; Adriani, A.; Allegrini, F. et al

in Science (2017), 356(6340), 826--832

Jupiter is the largest and most massive planet in our solar system. NASA\textquoterights Juno spacecraft arrived at Jupiter on 4 July 2016 and made its first close pass on 27 August 2016. Bolton et al ... [more ▼]

Jupiter is the largest and most massive planet in our solar system. NASA\textquoterights Juno spacecraft arrived at Jupiter on 4 July 2016 and made its first close pass on 27 August 2016. Bolton et al. present results from Juno\textquoterights flight just above the cloud tops, including images of weather in the polar regions and measurements of the magnetic and gravitational fields. Juno also used microwaves to peer below the visible surface, spotting gas welling up from the deep interior. Connerney et al. measured Jupiter\textquoterights aurorae and plasma environment, both as Juno approached the planet and during its first close orbit.Science, this issue p. 821, p. 826The Juno spacecraft acquired direct observations of the jovian magnetosphere and auroral emissions from a vantage point above the poles. Juno\textquoterights capture orbit spanned the jovian magnetosphere from bow shock to the planet, providing magnetic field, charged particle, and wave phenomena context for Juno\textquoterights passage over the poles and traverse of Jupiter\textquoterights hazardous inner radiation belts. Juno\textquoterights energetic particle and plasma detectors measured electrons precipitating in the polar regions, exciting intense aurorae, observed simultaneously by the ultraviolet and infrared imaging spectrographs. Juno transited beneath the most intense parts of the radiation belts, passed about 4000 kilometers above the cloud tops at closest approach, well inside the jovian rings, and recorded the electrical signatures of high-velocity impacts with small particles as it traversed the equator. [less ▲]

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See detailJupiter's Magnetotail
Krupp, Norbert; Kronberg, Elena; Radioti, Aikaterini ULiege

in AGU Monograph (2014)

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See detailJupiter’s main auroral emission; local time and temporal variability
Grodent, Denis ULiege; Radioti, Aikaterini ULiege; Bonfond, Bertrand ULiege et al

Conference (2008, September 23)

Jupiter's main auroral oval is associated with the ionosphere-magnetosphere coupling current system which is related to the breakdown of corotation in the middle magnetosphere. Its auroral footpath is ... [more ▼]

Jupiter's main auroral oval is associated with the ionosphere-magnetosphere coupling current system which is related to the breakdown of corotation in the middle magnetosphere. Its auroral footpath is usually represented as a smooth line closing around the pole. However, this simplistic view is misleading in many regards. We have constructed a new reference contour in the northern hemisphere (Figure 1), based on more than 1000 HST/UV images, which does not look like an oval and does not close around the pole. We use this reference contour to quantify the effects of temporal and local time variability of the magnetospheric plasma characteristics on the location of the main auroral emission. Beyond the orbit of Ganymede (15RJ), two key ingredients are expected to have a measurable influence on the instantaneous shape of the main emission contour: the azimuthal current flowing in the current sheet [1,2] and the corotation breakdown distance. The former affects the radial extent of the magnetic field lines, and the latter determines the radial location of the field aligned currents transmitting momentum from the planet to the lagging plasma. So far, models used to magnetically map the auroral main emission between the ionosphere and the equatorial plane assumed that these two parameters are constant and axisymmetric. However, in situ observations, mainly by Galileo, have revealed large local time asymmetries and temporal variations in the plasma flows and distribution. These variations have an impact on the azimuthal current and the distance at which the plasma angular velocity becomes significantly smaller than planetary rotation. We use a new magnetic field model [3], inherited from VIP4 and including a magnetic anomaly in the northern hemisphere, to simulate the effects of these asymmetries on the location of the main auroral emission, and interpret the large scattering of the corresponding HST data point. [less ▲]

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See detailJupiter's main auroral oval observed with HST-STIS
Grodent, Denis ULiege; Clarke, J. T.; Kim, J. et al

in Journal of Geophysical Research. Space Physics (2003), 108(A11),

An extended series of FUV images obtained on 7 days during winter 2000-2001, with fixed pointing, yielded highly accurate tracking of emisson features as Jupiter rotated. They provided newly detailed ... [more ▼]

An extended series of FUV images obtained on 7 days during winter 2000-2001, with fixed pointing, yielded highly accurate tracking of emisson features as Jupiter rotated. They provided newly detailed measurements of the degree of corotation of auroral emissions and their variations with changing central meridian longitude. This 2-month data set provides a statistical average location of the auroral emission and leads to the definition of new "reference ovals.'' The overall auroral morphology pattern is shown to be fixed in System-III longitude and unchanged over a 5-year period. When arranged in central meridian longitude ranges, the images show a significant contraction of the northern main oval as the central meridian longitude increases from 115 to 255degrees. The main auroral oval brightness is globally very stable in comparison with its terrestrial counterpart. It is shown to vary with magnetic local time, increasing from noon to dusk and then decreasing again in the magnetic evening. Hectometric emissions observed simultaneously with Galileo and Cassini reveal interplanetary shocks propagating outward from the Sun which may be related to the contraction of the main auroral oval observed in the HST images taken on 14 December 2000. In addition, we find that a brightening and a significant contraction of the main oval observed on 13 January 2001 corresponded to a time of increased solar wind dynamic pressure. [less ▲]

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See detailJupiter’s main auroral oval: what main oval?
Grodent, Denis ULiege; Gérard, Jean-Claude ULiege; Radioti, Aikaterini ULiege et al

Poster (2007, April 15)

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See detailJupiter’s polar auroral dynamics
Grodent, Denis ULiege; Bonfond, Bertrand ULiege

in AAS/Division for Planetary Sciences Meeting Abstracts (2014, November 01)

The morphology of Jupiter’s ultraviolet aurora is commonly described in terms of components located inside (poleward of) or outside (equatorward of) the main oval emission. These components may also be ... [more ▼]

The morphology of Jupiter’s ultraviolet aurora is commonly described in terms of components located inside (poleward of) or outside (equatorward of) the main oval emission. These components may also be discriminated by their temporal behaviour, where the narrowest parts of the main “oval” remain relatively stable over time periods of several hours, and the satellite footprints show large variability with timescales of minutes. Inside the main emission the so-called polar aurora, presumably corresponding to the polar cap mixing open and closed magnetic field lines, is characterized by rapid motions taking the form of swirls, giving rise to the “swirl region” and by intermittent brightenings in the “active region”. Coarse analysis of these motions suggests that they are too fast to respond to an equatorial magnetospheric forcing. Instead, they appear to be related to processes taking place in or above the ionosphere where distances travelled by plasma waves match those of the subtended auroral emission. Here, we present a preliminary improved analysis of the auroral motion in the polar region based on the application of an iterative “Advection Corrected Correlation Image Velocimetry” (ACCIV) method (Asay-Davis et al., 2009). This method allows one to build velocity fields quantifying local and overall auroral motions which may then be used to constrain their origin. [less ▲]

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See detailJupiter's polar auroral emissions
Grodent, Denis ULiege; Clarke, J. T.; Waite, J. H. et al

in Journal of Geophysical Research. Space Physics (2003), 108(A10),

[1] This paper reports a study of Jupiter's polar auroral emissions observed in an extended series of FUV images. They were obtained on seven days, during winter 2000-2001, with the STIS camera on board ... [more ▼]

[1] This paper reports a study of Jupiter's polar auroral emissions observed in an extended series of FUV images. They were obtained on seven days, during winter 2000-2001, with the STIS camera on board the Hubble Space Telescope. The fixed pointing yielded highly accurate and consistent tracking of emisson features as Jupiter rotated, allowing the analysis of the auroral morphology and brightness on timescales ranging from seconds to days. In the Northern Hemisphere, the polar emissions, located poleward of the main oval, usually represent about 30% of the total auroral FUV emitted power. They show emission bursts lasting similar to100 s, while the main oval remains stable. The polar region may be divided into three regions apparently fixed in magnetic local time: the dawnside dark region, the poleward swirl region, and the duskside active region in which flares and arc-like features are observed. Each of these UV emission regions can be identified with its infrared counterpart and probably relates to a different sector of the Dungey cycle or Vasyliunas cycle plasma flows. [less ▲]

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See detailJupiter’s polar auroral emissions-signatures of magnetic reconnection
Radioti, Aikaterini ULiege; Gérard, Jean-Claude ULiege; Grodent, Denis ULiege et al

Conference (2007, August 23)

The polar auroral emissions at Jupiter can be divided into three regions fixed in mag- netic local time: the dawnside dark region, the poleward swirl region and the duskside active region in which flares ... [more ▼]

The polar auroral emissions at Jupiter can be divided into three regions fixed in mag- netic local time: the dawnside dark region, the poleward swirl region and the duskside active region in which flares and arc-like features are observed. Previous studies re- lated the polar emissions to the solar wind driven Dungey cycle and Vasyliunas flow cycle. Based on HST STIS and ACS images we study extensively the time variations of the morphology and brightness of various polar auroral features as well as their duration and reoccurrence. We magnetically map their location in the equatorial plane and we compare their spatial size and time scales with the reconnection events taking place in the Jovian magnetotail. We discuss the possibility that some polar auroral features are signatures of magnetic reconnection. [less ▲]

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See detailJupiter's Polar Cap Aurora
Grodent, Denis ULiege; Bonfond, Bertrand ULiege

Scientific conference (2014, November 18)

The morphology of Jupiter’s ultraviolet aurora is commonly described in terms of components located inside (poleward of) or outside (equatorward of) the main oval emission. These components may also be ... [more ▼]

The morphology of Jupiter’s ultraviolet aurora is commonly described in terms of components located inside (poleward of) or outside (equatorward of) the main oval emission. These components may also be discriminated by their temporal behaviour, where the narrowest parts of the main “oval” remain relatively stable over time periods of several hours, and the satellite footprints show large variability with timescales of minutes. Inside the main emission the so-called polar aurora, presumably corresponding to the polar cap mixing open and closed magnetic field lines, is characterized by rapid motions taking the form of swirls, giving rise to the “swirl region” and by intermittent brightenings in the “active region”. Coarse analysis of these motions suggests that they are too fast to respond to an equatorial magnetospheric forcing. Instead, they appear to be related to processes taking place in or above the ionosphere where distances travelled by plasma waves match those of the subtended auroral emission. Here, we present a preliminary improved analysis of the auroral motion in the polar region based on the application of an iterative “Advection Corrected Correlation Image Velocimetry” (ACCIV) method (Asay-Davis et al., 2009). This method allows one to build velocity fields quantifying local and overall auroral motions which may then be used to constrain their origin. [less ▲]

Detailed reference viewed: 18 (2 ULiège)
See detailJupiter's Thermospheric General Circulation Model (JTGCM): Equatorial thermal structure in comparison with Galileo probe measurements
Majeed, T.; Bougher, S. W.; Waite, J. H. et al

Poster (2001, June 25)

Detailed reference viewed: 3 (0 ULiège)
See detailJupiter's ultraviolet polar auroral emissions
Coumans, Valérie ULiege; Bonfond, Bertrand ULiege; Grodent, Denis ULiege et al

Conference (2009, September)

Detailed reference viewed: 16 (6 ULiège)
See detailJupiter's ultraviolet polar emission: a statistical study
Coumans, Valérie ULiege; Bonfond, Bertrand ULiege; Grodent, Denis ULiege et al

Conference (2010, September)

Detailed reference viewed: 12 (5 ULiège)
See detailJurés de prix littéraires. Liens et figurations
Dozo, Björn-Olav ULiege

Conference given outside the academic context (2013)

Detailed reference viewed: 24 (4 ULiège)
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See detailLa juridiction de l’Ordre de Cîteaux sur les communautés de la branche féminine aux Pays-Bas et dans la principauté de Liège : 15e-18e s.
Henneau, Marie-Elisabeth ULiege

in Henneau, Marie-Elisabeth; Barrière, Bernadette; Bonis, Armelle (Eds.) et al Cîteaux et les femmes (2001)

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See detailJuridiction ordinaire et juridiction administrative en droit belge
Pâques, Michel ULiege; Donnay, Luc ULiege

in Chroniques de Droit Public = Publiekrechtelijke Kronieken (2007)

Detailed reference viewed: 60 (15 ULiège)
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See detailJuridiction ordinaire et juridiction administrative en droit belge
Pâques, Michel ULiege; Donnay, Luc ULiege

in Ben Salah, Hafedh; Ridha Jenayah, Mohamed (Eds.) La justice administrative dans les pays du Maghreb, la réception du modèle européen (2008)

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See detailLes juridictions constitutionnelles suprêmes dans les États fédéraux : créatures et créateurs de fédéralisme
Bouhon, Frédéric ULiege

in Fédéralisme - Régionalisme (2018), 17(2017),

Ce numéro de la Revue "Fédéralisme Régionalisme" publie les résultats d'une étude de droit comparé sur les cours constitutionnelles dans les États fédéraux. Il s'agit d'une étude collective qui porte sur ... [more ▼]

Ce numéro de la Revue "Fédéralisme Régionalisme" publie les résultats d'une étude de droit comparé sur les cours constitutionnelles dans les États fédéraux. Il s'agit d'une étude collective qui porte sur huit États : les États-Unis d'Amérique, la Canada, l'Inde, l'Australie, l'Allemagne, l'Autriche, la Suisse et la Belgique. L'étude montre tant les implications du caractère fédéral de l'État sur la conception de la juridiction constitutionnelle suprême que l'influence de cette dernière sur la dynamique fédérale. [less ▲]

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See detailLes juridictions d'instruction
Chichoyan, Daisy ULiege

in Postal Memorialis (2007), J38

Etude systématique des juridictions d'instruction

Detailed reference viewed: 52 (2 ULiège)