References of "Gérard, Jean-Claude"
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See detailStagnation of Saturn's auroral emission at noon
Radioti, Aikaterini ULiege; Grodent, Denis ULiege; Gérard, Jean-Claude ULiege et al

in Journal of Geophysical Research. Space Physics (2017)

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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 detailResponse of Jupiter's auroras to conditions in the interplanetary medium as measured by the Hubble Space Telescope and Juno
Nichols, J. D.; Badman, S. V.; Bagenal, F. et al

in Geophysical Research Letters (2017)

We present the first comparison of Jupiter's auroral morphology with an extended, continuous and complete set of near-Jupiter interplanetary data, revealing the response of Jupiter's auroras to the ... [more ▼]

We present the first comparison of Jupiter's auroral morphology with an extended, continuous and complete set of near-Jupiter interplanetary data, revealing the response of Jupiter's auroras to the interplanetary conditions. We show that for ∼1-3 days following compression region onset the planet's main emission brightened. A duskside poleward region also brightened during compressions, as well as during shallow rarefaction conditions at the start of the program. The power emitted from the noon active region did not exhibit dependence on any interplanetary parameter, though the morphology typically differed between rarefactions and compressions. The auroras equatorward of the main emission brightened over ∼10 days following an interval of increased volcanic activity on Io. These results show that the dependence of Jupiter's magnetosphere and auroras on the interplanetary conditions are more diverse than previously thought. [less ▲]

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See detailJuno-UVS Approach Observations of Jupiter's Auroras
Gladstone, G. R.; Versteeg, M. H.; Greathouse, T. K. et al

in Geophysical Research Letters (2017)

Juno-UVS observations of Jupiter's aurora obtained during approach are presented. Prior to the bow-shock crossing on 24 June 2016, the Juno approach provided a rare opportunity to correlate local solar ... [more ▼]

Juno-UVS observations of Jupiter's aurora obtained during approach are presented. Prior to the bow-shock crossing on 24 June 2016, the Juno approach provided a rare opportunity to correlate local solar wind conditions with Jovian auroral emissions. Some of Jupiter's auroral emissions are expected to be controlled or modified by local solar wind conditions. Here we compare synoptic Juno-UVS observations of Jupiter's auroral emissions, acquired during 3-29 June 2016, with in situ solar wind observations, and related Jupiter observations from Earth. Four large auroral brightening events are evident in the synoptic data, in which the total emitted auroral power increases by a factor of 3-4 for a few hours. Only one of these brightening events correlates well with large transient increases in solar wind ram pressure. The brightening events which are not associated with the solar wind generally have a rise time of ~2 hours and a decay time of ~5 hours. [less ▲]

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See detailSeasonal Transport in Mars’ Mesosphere revealed by Nitric Oxide Nightglow vertical profiles and global images from IUVS/MAVEN
Stiepen, Arnaud ULiege; Stewart; Jain et al

Conference (2017)

We analyze the ultraviolet nightglow in the atmosphere of Mars through Nitric Oxide (NO) δ and γ bands emis- sions. On the dayside thermosphere of Mars, solar extreme ultraviolet radiation partly ... [more ▼]

We analyze the ultraviolet nightglow in the atmosphere of Mars through Nitric Oxide (NO) δ and γ bands emis- sions. On the dayside thermosphere of Mars, solar extreme ultraviolet radiation partly dissociates CO2 and N2 molecules. O(3P) and N(4S) atoms are carried by the day-to-night hemispheric transport. They preferentially descend in the nightside mesosphere in the winter hemisphere, where they can radiatively recombine to form NO(C2Π). The excited molecules promptly relax by emitting photons in the UV δ bands and in the γ bands through cascades via the A2Σ, v’ = 0 state. These emissions are thus indicators of the N and O atom fluxes transported from the dayside to Mars’ nightside and the winter descending circulation pattern from the nightside thermosphere to the mesosphere (e.g. Bertaux et al., 2005 ; Bougher et al., 1990 ; Cox et al., 2008 ; Gagné et al., 2013 ; Gérard et al., 2008 ; Stiepen et al., 2015). Observations of these emissions have been accumulated on a large dataset of nightside disk images and vertical profiles obtained at the limb by the Imaging Ultraviolet Spectrograph (IUVS, McClintock et al., 2015) instrument when the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft is at its apoapsis and its periapsis phases along its orbit, respectively. We present discussion on the variability in the brightness, altitude and topside scale height of the emission with season, geographical position and local time and possible interpretation for local and global changes in the meso- sphere dynamics. IUVS images and limb scans reveal unexpected complex structure of the emission. The brightest emission is observed close to the winter pole. The emission is also surprisingly more intense in some sectors located close to the equator : at 120 ̊ and 150 ̊ longitude. Observations also reveal spots and streaks, indicating irregularities in the wind circulation pattern and possible impact of waves and tides. The disk images and limb profiles are compared to the LMD-MGCM model (Gonzàlez-Galindo et al., 2009 ; Lopez-Valverde et al., 2011) to focus on the seasonal, local time and geographical influences on the NO Nightglow emission. We will also provide a statistical study of the regions of enhanced brightness (i.e. splotches and streaks) and discuss possible interpretation from the comparison to the GCM. [less ▲]

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See detailInfluence of the crustal magnetic field on the Mars aurora electron flux and UV brightness
Bisikalo, D. V.; Shematovich, V. I.; Gérard, Jean-Claude ULiege et al

in Icarus (2017), 282

Observations with the SPICAM instrument on board Mars Express have shown the occasional presence of localized ultraviolet nightside emissions associated with enhanced energetic electron fluxes. These ... [more ▼]

Observations with the SPICAM instrument on board Mars Express have shown the occasional presence of localized ultraviolet nightside emissions associated with enhanced energetic electron fluxes. These features generally occur in regions with significant radial crustal magnetic field. We use a Monte-Carlo electron transport model to investigate the role of the magnetic field on the downward and upward electron fluxes, the brightness and the emitted power of auroral emissions. Simulations based on an ASPERA-3 measured auroral electron precipitation indicate that magnetic mirroring leads to an intensification of the energy flux carried by upward moving electrons- from about 20% in the absence of crustal magnetic field up to 33-78% when magnetic field is included depending on magnetic field topology. Conservation of the particle flux in a flux tube implies that the presence of the B-field does not appreciably modify the emission rate profiles for an initially isotropic pitch angle distribution. However, we find that crustal magnetic field results in increase of the upward electron flux, and, consequently, in reduction of the total auroral brightness for given energy flux of precipitating electrons. [less ▲]

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See detailThe complex behavior of the satellite footprints at Jupiter: the result of universal processes?
Bonfond, Bertrand ULiege; Grodent, Denis ULiege; Badman, Sarah V. et al

Poster (2016, December 14)

At Jupiter, some auroral emissions are directly related to the electromagnetic interaction between the moons Io, Europa and Ganymede on one hand and the rapidly rotating magnetospheric plasma on the other ... [more ▼]

At Jupiter, some auroral emissions are directly related to the electromagnetic interaction between the moons Io, Europa and Ganymede on one hand and the rapidly rotating magnetospheric plasma on the other hand. Out of the three, the Io footprint is the brightest and the most studied. Present in each hemisphere, it is made of at least three different spots and an extended trailing tail. The variability of the brightness of the spots as well as their relative location has been tentatively explained with a combination of Alfvén waves’ partial reflections on density gradients and bi-directional electron acceleration at high latitude. Should this scenario be correct, then the other footprints should also show the same behavior. Here we show that all footprints are, at least occasionally, made of several spots and they all display a tail. We also show that these spots share many characteristics with those of the Io footprint (i.e. some significant variability on timescales of 2-3 minutes). Additionally, we present some Monte-Carlo simulations indicating that the tails are also due to Alfvén waves electron acceleration rather than quasi-static electron acceleration. Even if some details still need clarification, these observations strengthen the scenario proposed for the Io footprint and thus indicate that these processes are universal. In addition, we will present some early results from Juno-UVS concerning the location and morphology of the footprints during the first low-altitude observations of the polar aurorae. These observations, carried out in previously unexplored longitude ranges, should either confirm or contradict our understanding of the footprints. [less ▲]

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See detailJupiter’s auroras during the Juno approach phase as observed by the Hubble Space Telescope
Nichols, Jonathan D; Clarke, John T; Orton, Glennn S et al

Conference (2016, December 13)

We present movies of the Hubble Space Telescope (HST) observations of Jupiter’s FUV auroras observed during the Juno approach phase and first capture orbit, and compare with Juno observations of the ... [more ▼]

We present movies of the Hubble Space Telescope (HST) observations of Jupiter’s FUV auroras observed during the Juno approach phase and first capture orbit, and compare with Juno observations of the interplanetary medium near Jupiter and inside the magnetosphere. Jupiter’s FUV auroras indicate the nature of the dynamic processes occurring in Jupiter’s magnetosphere, and the approach phase provided a unique opportunity to obtain a full set of interplanetary data near to Jupiter at the time of a program of HST observations, along with the first simultaneous with Juno observations inside the magnetosphere. The overall goal was to determine the nature of the solar wind effect on Jupiter’s magnetosphere. HST observations were obtained with typically 1 orbit per day over three intervals: 16 May – 7 June, 22-30 June and 11-18 July, i.e. while Juno was in the solar wind, around the bow shock and magnetosphere crossings, and in the mid-latitude middle-outer magnetospheres. We show that these intervals are characterised by particularly dynamic polar auroras, and significant variations in the auroral power output caused by e.g. dawn storms, intense main emission and poleward forms. We compare the variation of these features with Juno observations of interplanetary compression regions and the magnetospheric environment during the intervals of these observations. [less ▲]

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See detailInitial observations of Jupiter’s aurora from Juno’s Ultraviolet Spectrograph (Juno-UVS)
Gladstone, Randy; Versteeg; Greathouse, Thomas et al

Conference (2016, December 13)

Juno-UVS is an imaging spectrograph with a bandpass of 70<λ<205 nm. This wavelength range includes important far-ultraviolet (FUV) emissions from the H2 bands and the H Lyman series which are produced in ... [more ▼]

Juno-UVS is an imaging spectrograph with a bandpass of 70<λ<205 nm. This wavelength range includes important far-ultraviolet (FUV) emissions from the H2 bands and the H Lyman series which are produced in Jupiter’s auroras, and also the absorption signatures of aurorally-produced hydrocarbons. The Juno-UVS instrument telescope has a 4x4 cm2 input aperture and uses an off-axis parabolic primary mirror. A flat scan mirror situated near the entrance of the telescope is used to observe at up to ±30° perpendicular to the Juno spin plane. The light is focused onto the spectrograph entrance slit, which has a “dog-bone” shape, with three sections of 2.55°x0.2°, 2.0°x0.025°, and 2.55°x0.2° (as projected onto the sky). Light entering the slit is dispersed by a toroidal grating which focuses FUV light onto a curved microchannel plate (MCP) cross delay line (XDL) detector with a solar blind UV-sensitive CsI photocathode. The two mirrors and the grating are coated with MgF2 to improve FUV reflectivity. Tantalum surrounds the spectrograph assembly to shield the detector and its electronics from high-energy electrons. All other electronics are located in Juno’s spacecraft vault, including redundant low-voltage and high-voltage power supplies, command and data handling electronics, heater/actuator electronics, scan mirror electronics, and event processing electronics. The purpose of Juno-UVS is to remotely sense Jupiter’s auroral morphology and brightness to provide context for in situ measurements by Juno’s particle instruments. Here we present the first near-Jupiter results from the UVS instrument following measurements made during PJ1, Juno’s first perijove pass with its instruments powered on and taking data. [less ▲]

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See detailSearch for low-latitude atmospheric hydrocarbon variations on Jupiter from Juno-UVS measurements
Hue, Vincent; Gladstone, Randy; Greathouse, Thomas et al

Conference (2016, December 13)

The Juno mission offers the opportunity to study Jupiter, from its inner structure, up to its magnetospheric environment. Juno was launched on August 2011 and its Jupiter orbit insertion (JOI) occurred on ... [more ▼]

The Juno mission offers the opportunity to study Jupiter, from its inner structure, up to its magnetospheric environment. Juno was launched on August 2011 and its Jupiter orbit insertion (JOI) occurred on July 4th 2016. The nominal Juno mission involves 35 science polar-orbits of 14-days period, with perijove and apojove distances located at 0.06 Rj and 45 Rj, respectively. Juno-UVS is a UV spectrograph with a bandpass of 70<λ<205 nm, designed to characterize Jupiter UV emissions. One of the main additions of UVS compared to its predecessors (New Horizons- and Rosetta- Alice, LRO-LAMP) is a 2.54 mm tantalum shielding, to protect it from the harsh radiation environment at Jupiter, and a scan mirror, to allow for targeting specific auroral and atmospheric features at +/- 30˚ perpendicular to the Juno spin plane. It will provide new constraints on Jupiter’s auroral morphology, spectral features, and vertical structure, while providing remote-sensing constraints for the onboard waves and particle instruments. It will also be used to probe upper-atmospheric composition through absorption features found in the UV spectra using reflected solar UV radiation. For example, stratospheric hydrocarbons such as C2H2 and C2H6 are known to absorb significantly in the 150-180 nm regions, and these absorption features can be used to determine their abundances. We will present our search for the spectroscopic features seen in Jupiter’s reflected sunlight during the first perijove. [less ▲]

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See detailDynamics of the flares in the active polar region of Jupiter
Bonfond, Bertrand ULiege; Grodent, Denis ULiege; Badman, S. V. et al

in Geophysical Research Letters (2016)

The dusk-side of the polar region of Jupiter's UV aurorae, called the active region, sometimes exhibits quasi-periodic (QP) flares on time-scales of 2-3 minutes. Based on Hubble Space Telescope Far-UV ... [more ▼]

The dusk-side of the polar region of Jupiter's UV aurorae, called the active region, sometimes exhibits quasi-periodic (QP) flares on time-scales of 2-3 minutes. Based on Hubble Space Telescope Far-UV time-tag images, we show for the first time that the northern hemisphere also displays QP-flares. The area covered by these flares can reach up to 2.4 × 108 km2 (i.e. the whole active region), but often only involves an area an order of magnitude smaller. Using a magnetic field mapping model, we deduced that these areas correspond to the dayside outer magnetosphere. In our dataset, quasi-periodic features are only seen on half of the cases and even on a given observation, a region can be quiet for one half and blinking on the other half. Consecutive observations in the two hemispheres show that the brightening can occur in phase. Combined with the size and location of the flares, this behaviour suggests that the QP-flares most likely take place on closed magnetic field lines. [less ▲]

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See detailLimb observations with NOMAD (UV,visible, IR)
Gérard, Jean-Claude ULiege; Soret, Lauriane ULiege

Scientific conference (2016, December)

We examine the possibilities and conditions to observe the Mars airglow and aurora (dayside and nightside) at the limb with the NOMAD instrument on board the TGO/EXOMARS orbiter.

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See detailFirst Hubble Space Telescope Movies of Jupiter’s Ultraviolet Aurora During the NASA Juno Prime Mission
Grodent, Denis ULiege; Gladstone, G. Randall; Clarke, John T. et al

Poster (2016, December)

The primary goal of this HST campaign is to complement Juno-UVS (Ultraviolet Spectrograph) observations. This complementarity is four-fold as HST observes Jupiter’s aurora when: 1) Juno-UVS is turned off ... [more ▼]

The primary goal of this HST campaign is to complement Juno-UVS (Ultraviolet Spectrograph) observations. This complementarity is four-fold as HST observes Jupiter’s aurora when: 1) Juno-UVS is turned off, that is about 98% of Juno’s 14-day orbit, and Juno’s in situ instruments are in operation. 2) Juno-UVS is operating, but observes the opposite hemisphere of Jupiter. 3) UVS is on in the same hemisphere, but too close to Jupiter to have a global, contextual, view of the aurora and/or UVS is affected by the noise induced by Jupiter’s radiation belts. 4) Juno is too far from Jupiter to get a detailed view of the aurora. In addition, HST will observe the auroral and airglow emissions of the Galilean moons Io, Ganymede and Europa, when UVS is measuring their auroral footprints in Jupiter’s ionosphere. During this campaign, HST is obtaining 45-min STIS time-tag images -movies- of both hemispheres of Jupiter and STIS/COS spectra of Jupiter's moons. These observations are taking place during 4 sequences of Juno's orbit (Figure: typical orbit in magnetic coordinates): 1) Perijove segment: a 6-hour sequence bracketing the time of Juno's closest approach of Jupiter. 2) Crossing segments: few hours periods during which Juno is crossing the magnetic equator of Jupiter and in situ instruments are observing the plasma sheet particles. 3) Perijove +/- 1 Jovian rotation (or more), to provide a context for the auroral activity before and after perijove. 4) Apojove segment: a 12-hour period bracketing the time when Juno is farthest from Jupiter and Juno-UVS is continuously monitoring the global auroral UV power of Jupiter. During Juno orbit PJ5, between 28 Nov. and 07 Dec. 2016, HST obtains 9 STIS movies: 3 movies of the northern aurora near perijove, 1 movie (north) one Jovian rotation before and 2 movies (south- north) one and two Jovian rotations after perijove, 2 movies (north) during two close CS crossings, and 1 movie near apojove. These movies will be commented during this presentation. [less ▲]

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See detailThe Martian diffuse aurora: Monte Carlo simulations and comparison with IUVS-MAVEN observations
Gérard, Jean-Claude ULiege; Soret, Lauriane ULiege; Schneider, N. et al

Conference (2016, December)

A new type of Martian aurora, characterized by an extended spatial distribution, an altitude lower than the discrete aurora and electron precipitation up to 200 keV has been observed following solar ... [more ▼]

A new type of Martian aurora, characterized by an extended spatial distribution, an altitude lower than the discrete aurora and electron precipitation up to 200 keV has been observed following solar activity on several occasions with the IUVS on board the MAVEN spacecraft. We describe the results of Monte Carlo simulations of the production of several ultraviolet and visible auroral emissions for initial electron energies from 0.1 to 200 keV. These include the CO2+ ultraviolet doublet (UVD) at 288.3 and 289.6 nm and the Fox–Duffendack–Barker (FDB) bands, CO Cameron and Fourth Positive bands, OI 130.4 and 297.2 nm and CI 156.1 nm and 165.7 nm multiplets. We calculate the nadir and limb intensities of several of these emissions for a unit precipitated energy flux. Our results indicate that electrons in the range 100-200 keV produce maximum CO2+ UVD emission near 75 km. We combine SWEA and SEP electron energy spectra measured during diffuse aurora to calculate the volume emission rates and compare with IUVS observations of the emission limb profiles. The strongest predicted emissions are the CO2+ FDB, UVD and the CO Cameron bands. The metastable a 3Π state which radiates the Cameron bands is deactivated by collisions below ~110 km. As a consequence, we show that the CO2+ UVD to the Cameron bands ratio increases at low altitude in the energetic diffuse aurora. [less ▲]

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See detailPulsations of the polar cusp aurora at Saturn
Palmaerts, Benjamin ULiege; Radioti, Aikaterini ULiege; Roussos, E. et al

in Journal of Geophysical Research. Space Physics (2016), 121

The magnetospheric cusp is a region connecting the interplanetary environment to the ionosphere and enabling solar wind particles to reach the ionosphere. We report the detection of several isolated high ... [more ▼]

The magnetospheric cusp is a region connecting the interplanetary environment to the ionosphere and enabling solar wind particles to reach the ionosphere. We report the detection of several isolated high-latitude auroral emissions with the Ultraviolet Imaging Spectrograph of the Cassini spacecraft. We suggest that these auroral spots, located in the dawn-to-noon sector and poleward of the main emission, are the ionospheric signatures of the magnetospheric cusp, in agreement with some previous observations with the Hubble Space Telescope. The high-latitude cusp auroral signature has been associated with high-latitude lobe reconnection in the presence of a southward interplanetary magnetic field. The occurrence rate of the polar cusp aurora suggests that lobe reconnection is frequent at Saturn. Several auroral imaging sequences reveal a quasiperiodic brightening of the polar cusp aurora with a period in the range of 60 to 70 min. Similar pulsations in the energetic electron fluxes and in the azimuthal component of the magnetic field are simultaneously observed by Cassini instruments, suggesting the presence of field-aligned currents. Pulsed dayside magnetopause reconnection is a likely common triggering process for the cusp auroral brightenings at Saturn and the quasiperiodic pulsations in the high-latitude energetic electron fluxes. [less ▲]

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See detailNitric Oxide nightglow from IUVS disk images
Stiepen, Arnaud ULiege; Schneider; Gonzàlez-Galindo et al

Conference (2016, November)

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See detailJuno Ultraviolet Spectrograph (Juno-UVS) Observations of Jupiter during Approach
Gladstone, G. Randall; Versteeg, Maarten; Greathouse, Thomas K. et al

Conference (2016, October)

We present the initial results from Juno Ultraviolet Spectrograph (Juno-UVS) observations of Jupiter obtained during approach in June 2016. Juno-UVS is an imaging spectrograph with a bandpass of 70<λ<205 ... [more ▼]

We present the initial results from Juno Ultraviolet Spectrograph (Juno-UVS) observations of Jupiter obtained during approach in June 2016. Juno-UVS is an imaging spectrograph with a bandpass of 70<λ<205 nm. This wavelength range includes all important ultraviolet (UV) emissions from the H<SUB>2</SUB> bands and the H Lyman series which are produced in Jupiter's auroras, and also the absorption signatures of aurorally-produced hydrocarbons. The Juno-UVS instrument telescope has a 4 x 4 cm<SUP>2</SUP> input aperture and uses an off-axis parabolic primary mirror. A flat scan mirror situated near the entrance of the telescope is used to observe at up to ±30° perpendicular to the Juno spin plane. The light is focused onto the spectrograph entrance slit, which has a "dog-bone" shape 7.2° long, in three sections of 0.2°, 0.025°, and 0.2° width (as projected onto the sky). Light entering the slit is dispersed by a toroidal grating which focuses UV light onto a curved microchannel plate (MCP) cross delay line (XDL) detector with a solar blind UV-sensitive CsI photocathode. Tantalum surrounds the spectrograph assembly to shield the detector and its electronics from high-energy electrons. All other electronics are located in Juno's spacecraft vault, including redundant low-voltage and high-voltage power supplies, command and data handling electronics, heater/actuator electronics, scan mirror electronics, and event processing electronics. The purpose of Juno-UVS is to remotely sense Jupiter's auroral morphology and brightness to provide context for in situ measurements by Juno's particle instruments. Prior to Jupiter Orbit Insertion (JOI) on July 5, Juno approach observations provide a rare opportunity to correlate local solar wind conditions with Jovian auroral emissions. Some of Jupiter's auroral emissions (e.g., polar emissions) may be controlled or at least affected by the solar wind. Here we compare synoptic Juno-UVS observations of Jupiter's auroral emissions (~40 minutes per hour, acquired during 2016 June 3-30) with in situ solar wind observations, as well as related Jupiter observations obtained from Earth. [less ▲]

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See detailCassini UVIS Auroral Observations in 2016
Pryor, Wayne R.; Jouchoux, Alain; Esposito, Larry et al

Conference (2016, October)

In June of 2016, the Cassini Saturn orbiter began a series of high inclination orbits that will continue until September 2017 when the mission ends as Cassini enters the Saturn atmosphere. These orbits ... [more ▼]

In June of 2016, the Cassini Saturn orbiter began a series of high inclination orbits that will continue until September 2017 when the mission ends as Cassini enters the Saturn atmosphere. These orbits present excellent views of Saturn's polar regions suitable for auroral imaging at the closest distances to date, with the additional prospect of simultaneous particle and fields measurements within the sources of Saturn Kilometric Radiation (SKR) associated with ultraviolet auroral emissions and/or acceleration regions likely coinciding with them. We will present new Cassini Ultraviolet Imaging Spectrograph (UVIS) auroral images, spectra and movies obtained during the summer and fall of 2016 and put them in the context of auroral data collected since Cassini orbit insertion in 2004. Included in the new data will be UVIS south polar observations obtained simultaneously with Hubble Space Telescope observations of the north polar region on June 29, 2016 and August 19, 2016. [less ▲]

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See detailUV emissions of Jupiter: exploration of the high-latitude regions through the UV spectrograph on NASA's Juno mission
Hue, Vincent; Gladstone, G. Randall; Versteeg, Maarten et al

Conference (2016, October)

The Juno mission offers the opportunity to study Jupiter, from its inner structure to its magnetospheric environment. Juno was launched on August 2011 and its Jupiter orbit insertion (JOI) planned for ... [more ▼]

The Juno mission offers the opportunity to study Jupiter, from its inner structure to its magnetospheric environment. Juno was launched on August 2011 and its Jupiter orbit insertion (JOI) planned for July 4th 2016, will place Juno in a 53.5 days capture orbit. A period reduction maneuver will be performed two orbits later to place Juno into 14-days elliptical orbits for the duration of the nominal mission, which includes 36 orbits. Juno-UVS is a UV spectrograph with a bandpass of 70 ≤ λ ≤ 205 nm, designed to characterize Jupiter UV emissions. One of the main additions of UVS compared to its predecessors is a 2.54 mm tantalum shielding, to protect it from the harsh radiation environment at Jupiter, and a scan mirror, to allow for targeting specific auroral regions during perijove passes. The scan mirror is located at the front end of the instrument and will be used to look at +/- 30° perpendicular to the Juno spin plane. The entrance slit of UVS has a dog-bone shape composed by three sections with field of views of 0.2°x2.5°, 0.025°x2.0° and 0.2°x2.5°, as projected onto the sky. It will provide new constraints on Jupiter’s auroral nightside morphology and spectral features as well as the vertical structure of these emissions. It will bring remote-sensing constraints for the onboard waves and particle instruments (JADE, JEDI, Waves and MAG). The ability to change the pointing will allow relating the observed UV brightness of the regions magnetically connected to where Juno flies with the particles and waves measurements. We will discuss the planned observations and scientific targets for the nominal mission orbital sequence, which will consist of three UV datasets per orbit. We will present the results from the first orbit. As Juno orbit evolves during the mission, we will also present how these objectives evolve over time. [less ▲]

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See detailUVS – JIRAM image comparison during Juno PJ1
Gérard, Jean-Claude ULiege; Bonfond, Bertrand ULiege; Grodent, Denis ULiege et al

Conference (2016, September 27)

We present a comparison between images collected in the infrared and ultraviolet by the JIRAM and IUVS spectral imagers on board the Juno orbiter. Similarities and differences are pointed out.

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