Publications of Denis Grodent
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See detailAn Initial Survey of Juno-UVS Auroral Emission Spectra
Gladstone, Randy; Greathouse, Thomas; Versteeg, Maarten et al

Conference (2019, December 12)

We present an initial Juno-UVS survey of spectra of the major features of Jupiter’s ultraviolet auroras, which primarily include band emissions of H2 excited by electron impact, and the Lyman series of H ... [more ▼]

We present an initial Juno-UVS survey of spectra of the major features of Jupiter’s ultraviolet auroras, which primarily include band emissions of H2 excited by electron impact, and the Lyman series of H arising from electron impact dissociative excitation of H2. The primary difference found in most of the observed spectra is the column of hydrocarbons (mostly methane) overlying the aurora production layer in Jupiter’s atmosphere. This leads to the “color ratio” of the emissions, commonly defined as the ratio of auroral emissions at wavelengths 155-162 nm, where methane is transparent, to those at 125-130 nm, where methane is strongly absorbing. Over the course of the Juno mission, it has been found that the brightness of most auroral features known from previous observations from Earth orbit have a strong dependence on local time. The primary purpose of this survey is to examine if other details in the spectra of these features are likewise correlated with local time, and whether they are also sensitive to other changes, either in the precipitating particles (e.g., the mean electron energy) or in the auroral atmosphere (e.g., the ambient H2 vibrational distribution). [less ▲]

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See detailParticle Acceleration by Io’s Alfvénic Interaction (Invited)
Szalay, Jamey; Allegrini, Frederic; Bagenal, Fran et al

Conference (2019, December 12)

The Juno spacecraft crossed flux tubes connected to the Io footprint tail at a range of latitudes and altitudes. The Jovian Auroral Distributions Experiment (JADE) instrument onboard Juno made ... [more ▼]

The Juno spacecraft crossed flux tubes connected to the Io footprint tail at a range of latitudes and altitudes. The Jovian Auroral Distributions Experiment (JADE) instrument onboard Juno made observations of accelerated electrons and protons connected to the Io footprint tail aurora. JADE observed planetward electron energy fluxes of ~70 mW/m2 near the Io footprint, and ~10 mW/m2 farther down the tail, along with correlated, intense electric and magnetic wave signatures which also decreased in amplitude down the tail. All observed electron distributions were broad in energy, suggesting a dominantly broadband acceleration process, and did not show any inverted-V structure that would be indicative of acceleration by a quasi-static, discrete, parallel electric potential.Juno observed fine structure on scales of ~10s km, and confirmed independently with electron and wave measurements that a bifurcated tail can intermittently exist. Additionally, we report measurements that suggest proton acceleration is driven by Io’s Alfvénic interaction. While connected to Io’s footprint tail, JADE observed multiple proton populations accelerated in different magnetospheric locations, as well as a bifurcated proton tail structure. We will present these electron and proton observations and discuss how they fit into our evolving understanding of Io’s interaction with the Jovian magnetosphere. [less ▲]

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See detailObservations of Auroral “Raindrops” in Jupiter’s Polar Region by Juno-UVS
Hue, Vincent; Greathouse, Thomas; Gladstone, Randy et al

Poster (2019, December 11)

Juno-UVS has observed Jupiter’s FUV auroral emissions during multiple close flybys following Juno’s orbital insertion on 5 July 2016. Each perijove provides a different snapshot of the Jovian auroral ... [more ▼]

Juno-UVS has observed Jupiter’s FUV auroral emissions during multiple close flybys following Juno’s orbital insertion on 5 July 2016. Each perijove provides a different snapshot of the Jovian auroral emissions recorded at different system III longitudes and local time conditions. We present the analysis of an auroral feature identified in Jupiter’s polar region by Juno-UVS, characterized by faint (~100 kR) concentric circles of UV emission expanding with time. The features were found within Jupiter’s polar auroral regions, i.e. inside of the main oval, both in the northern and southern hemispheres. These regions, connected to Jupiter’s outer magnetosphere, are the most dynamic part of Jupiter’s UV-aurora often exhibiting flares evolving over short timescales. As Juno spins at a rate of 2 rpm, UVS provides snapshots of regions smaller than the main auroral regions. Consecutive spins recorded over the same region allow identification and characterization of these auroral features. We characterize where the “raindrops”-like features occur within the auroral region and determine their expansion rates. We use the Vogt et al. (2011, 2015) magnetosphere-ionosphere mapping model coupled with the JRM09 magnetic field model to trace the origin of these emissions back to their origin in the magnetodisk. We discuss potential physical interpretations of such features. [less ▲]

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See detailA Keogram Analysis of Local Time Variations of Jupiter’s Ultraviolet Aurora using Juno UVS Observations
Greathouse, Thomas; Gladstone, Randy; Versteeg, Maarten et al

Poster (2019, December 11)

With 20 successfully completed Perijoves, Juno UVS has collected an enormous amount of data with unprecedented views of the northern and southern auroras spanning all local time geometries. Juno UVS, with ... [more ▼]

With 20 successfully completed Perijoves, Juno UVS has collected an enormous amount of data with unprecedented views of the northern and southern auroras spanning all local time geometries. Juno UVS, with its spectral and spatial mapping capabilities allows for the retrieval of both UV brightness as well as color ratio information. Maps of both the brightness and color ratio of the main ovals and polar emissions display strong local time variations, some suggestive of ionospheric local time control while others magnetosphere local time drivers. In an attempt to quantitatively track the evolution of the auroral emission morphology and intensity, we have developed a process to create keograms of Jupiter’s auroral emissions. The keograms display a complicated evolution of northern and southern auroral emissions that depend not only on local time, but also on the overall state of the magnetosphere which varies perijove to perijove. We will present our method of producing the keograms and discuss insights we have drawn from them. Additionally, we present an attempt to trace the origin within the magnetodisk of the observed emissions via magnetic flux mapping using the Vogt et al. 2015 model updated to include the JRM09 magnetic field model. [less ▲]

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See detailDo Earth’s auroral substorms and Jupiter’s dawn storms arise from the same processes?
Bonfond, Bertrand ULiege; Yao, Zhonghua ULiege; Gladstone, Randy et al

Conference (2019, December 09)

For the first time, Juno has granted views of the night side aurora at Jupiter during several hours long observation sequences. Among the most spectacular events captured by Juno-UVS (the UltraViolet ... [more ▼]

For the first time, Juno has granted views of the night side aurora at Jupiter during several hours long observation sequences. Among the most spectacular events captured by Juno-UVS (the UltraViolet imaging Spectrograph on board Juno) are dawn storms. The images of these events show a striking resemblance to the sequence of events forming auroral substorms at Earth. They often start with transient north-south aligned features located poleward of the main oval. A few hours later, the post-midnight portion of the main arc brightens and forms a bead-like pattern. A few tens of minutes later, it then broadens both in latitude and in longitude, ultimately forming two separate arcs, one migrating poleward and one moving equatorward. At the same time, the whole feature, which first appeared fixed in local time, progressively accelerates towards co-rotation with the magnetic field. Finally, the equatorward part of the dawn storm transforms into large injection signatures. During this presentation, we will show in parallel similar sequences of terrestrial substorms and interpret these events in similar ways. Indeed, our thesis is that the two auroral events are the signatures of similar collapses of the magnetotail, even if the two systems did not accrue mass and energy through similar processes. Juno did more than observe the dawn storms from their initiation to their dissipation, the spacecraft also flew through the field lines connected to the auroral events. We will discuss the particle distributions and the enhancements of Alfvén wave activity that arose as Juno entered the heart of the storm. [less ▲]

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See detailAuroral Beads at Saturn and the Driving Mechanism: Cassini Proximal Orbits
Radioti, Aikaterini ULiege; Yao, Zhonghua ULiege; Grodent, Denis ULiege et al

in Astrophysical Journal (2019), 885

During the Grand Finale Phase of Cassini, the Ultraviolet Imaging Spectrograph on board the spacecraft detected repeated detached small- scale auroral structures. We describe these structures as auroral ... [more ▼]

During the Grand Finale Phase of Cassini, the Ultraviolet Imaging Spectrograph on board the spacecraft detected repeated detached small- scale auroral structures. We describe these structures as auroral beads, a term introduced in the terrestrial aurora. Those on DOY 232 2017 are observed to extend over a large range of local times, i.e., from 20 LT to 11 LT through midnight. We suggest that the auroral beads are related to plasma instabilities in the magnetosphere, which are often known to generate wavy auroral precipitations. Energetic neutral atom enhancements are observed simultaneously with auroral observations, which are indicative of a heated high pressure plasma region. During the same interval we observe conjugate periodic enhancements of energetic electrons, which are consistent with the hypothesis that a drifting interchange structure passed the spacecraft. Our study indicates that auroral bead structures are common phenomena at Earth and giant planets, which probably demonstrates the existence of similar fundamental magnetospheric processes at these planets. [less ▲]

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See detailJovian dawn storms and terrestrial auroral substorms: similarities and differences
Bonfond, Bertrand ULiege; Yao, Zhonghua ULiege; Gladstone, Randy et al

Conference (2019, September 18)

Juno's polar orbit allows us to contemplate a complete view of the Jovian aurorae for the first time. Here we mainly use observations from the ultraviolet spectrograph (Juno-UVS) in order to study one of ... [more ▼]

Juno's polar orbit allows us to contemplate a complete view of the Jovian aurorae for the first time. Here we mainly use observations from the ultraviolet spectrograph (Juno-UVS) in order to study one of the most spectacular features of Jupiter's aurorae: the dawn storms. Many of the properties of the dawn storms observed by Juno-UVS are similar to those of terrestrial substorms. [less ▲]

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See detailRecent Juno-UVS Observations of Jupiter's Auroras
Gladstone, Randy; Greathouse, Thomas; Versteeg, Maarten et al

Conference (2019, September 18)

Juno’s polar orbit provides excellent vantage pointsfor studying Jupiter’s bright and highly-variable far-ultraviolet (FUV) auroral emissions [1-3]. The Juno mission is a little over halfway through its ... [more ▼]

Juno’s polar orbit provides excellent vantage pointsfor studying Jupiter’s bright and highly-variable far-ultraviolet (FUV) auroral emissions [1-3]. The Juno mission is a little over halfway through its primary mission, and here we review some of the interesting results found so far by the Ultraviolet Spectrograph (UVS) instrument [4] during perijoves 1 and 3-21. [less ▲]

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See detailOn the 1-hour periodicities in the Saturnian system
Palmaerts, Benjamin ULiege; Roussos, E.; Grodent, Denis ULiege et al

Conference (2019, July 30)

The exploration of the magnetospheres of magnetized planets has revealed periodic phenomena with a large variety of periods. In Saturn's magnetosphere, oscillations with a period of about one hour are ... [more ▼]

The exploration of the magnetospheres of magnetized planets has revealed periodic phenomena with a large variety of periods. In Saturn's magnetosphere, oscillations with a period of about one hour are commonly identified in charged particle fluxes, in the magnetic field, in plasma waves and in the brightness of localized auroral structures. We will present a review of these 1-hour oscillations using multi-instrument observations acquired during the 13 years of the Cassini mission. We will discuss possible triggers in light of the Cassini observations of the 1-hour periodicities. The presence of 1-hour quasi-periodic electrons in the close vicinity of the magnetopause supports the involvement of magnetopause processes, such as magnetic reconnection and Kelvin-Helmholtz instabilities. Pulsed electrons are also encountered much deeper in the magnetosphere and may originate from reconnection in the magnetodisk, on both the day and night sides of the magnetosphere. Moreover, similar mechanisms might take place also in the magnetosphere of Jupiter, leading to the observed periodic phenomena. [less ▲]

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See detailCassini UVIS Detection of Saturn's North Polar Hexagon in the Grand Finale Orbits
Pryor, W. R.; Esposito, L. W.; Jouchoux, A. et al

in Journal of Geophysical Research. Planets (2019), 124

Cassini's final orbits in 2016 and 2017 provided unprecedented spatial resolution of Saturn's polar regions from near-polar spacecraft viewing geometries. Long-wavelength channels of Cassini's Ultraviolet ... [more ▼]

Cassini's final orbits in 2016 and 2017 provided unprecedented spatial resolution of Saturn's polar regions from near-polar spacecraft viewing geometries. Long-wavelength channels of Cassini's Ultraviolet Imaging Spectrograph instrument detected Saturn's UV-dark north polar hexagon near 180 nm at planetocentric latitudes near 75°N. The dark polar hexagon is surrounded by a larger, less UV-dark collar poleward of planetocentric latitude 65°N associated with the dark north polar region seen in ground-based images. The hexagon is closely surrounded by the main arc of Saturn's UV aurora. The UV-dark material was locally darkest on one occasion (23 January 2017) at the boundary of the hexagon; in most Ultraviolet Imaging Spectrograph images the dark material more uniformly fills the hexagon. The observed UV-dark stratospheric material may be a hydrocarbon haze produced by auroral ion-neutral chemistry at submicrobar pressure levels. Ultraviolet Imaging Spectrograph polar observations are sensitive to UV-absorbing haze particles at pressures lower than about 10-20 mbar. [less ▲]

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See detailJuno-UVS Observation of the Io Footprint During Solar Eclipse
Hue, V.; Greathouse, T. K.; Bonfond, Bertrand ULiege et al

in Journal of Geophysical Research (Space Physics) (2019), 124

The two main ultraviolet-signatures resulting from the Io-magnetosphere interaction are the local auroras on Io's atmosphere, and the Io footprints on Jupiter. We study here how Io's daily eclipses affect ... [more ▼]

The two main ultraviolet-signatures resulting from the Io-magnetosphere interaction are the local auroras on Io's atmosphere, and the Io footprints on Jupiter. We study here how Io's daily eclipses affect the footprint. Previous observations showed that its atmosphere collapses in eclipse. While remote observers can observe Io's local auroras briefly when Io disappears behind Jupiter, Juno is able to follow the Io footprint in the unlit hemisphere. Theoretical models of the variability of the energy flux fed into the Alfvén wings, ultimately powering the footprints, are not sufficiently constrained by observations. For the first time, we use observations of Io's footprint from the Ultraviolet Spectrograph (UVS) on Juno recorded as Io went into eclipse. We benchmark the trend of the footprint brightness using observations by UVS taken over Io's complete orbit and find that the footprint emitted power variation with Jupiter's rotation shows fairly consistent trends with previous observations. Two exploitable data sets provided measurements when Io was simultaneously in eclipse. No statistically significant changes were recorded as Io left and moved into eclipse, respectively, suggesting either that (i) Io's atmospheric densities within and outside eclipse are large enough to produce a saturated plasma interaction, that is, in the saturated state, changes in Io's atmospheric properties to first order do not control the total Alfvénic energy flux, (ii) the atmospheric collapse during the Juno observations was less than previously observed, or (iii) additional processes of the Alfvén wings in addition to the Poynting flux generated at Io control the footprint luminosity. <P /> [less ▲]

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See detailOrigin and triggers of the 1-hour electron pulsations in the Saturnian system
Palmaerts, Benjamin ULiege; Burkholder, B.; Delamere, P. A. et al

Conference (2019, June 07)

Phenomena displaying a periodicity of around one hour have been frequently observed in Saturn's magnetosphere during the Cassini era. In particular, flux of energetic electrons can exhibit 1-hour quasi ... [more ▼]

Phenomena displaying a periodicity of around one hour have been frequently observed in Saturn's magnetosphere during the Cassini era. In particular, flux of energetic electrons can exhibit 1-hour quasi-periodic pulsations. While these pulsations have been well characterized, their origin and the processes triggering them remained uncertain at the end of the Cassini mission. Using long imaging sequences of the auroral emissions at Saturn, we report the first direct observational evidence that the 1-hour periodicities arise from a global 1-hour oscillation of the Kronian magnetosphere. This natural oscillation acts independently of the local magnetospheric conditions and can have multiple triggering processes. Many 1-hour quasi-periodic electrons were encountered close to the magnetopause, suggesting that magnetopause processes could trigger them, such as magnetic reconnection and Kelvin-Helmholtz (KH) instabilities. We now report simultaneous presence of KH instabilities and 1-hour electron pulsations, supporting this scenario. Pulsed electrons are also encountered much deeper in the magnetosphere and may originate from reconnection in the magnetodisk, on both the day and night sides of the magnetosphere. [less ▲]

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See detailA nearly corotating long lasting auroral spiral at Saturn
Palmaerts, Benjamin ULiege; Yao, Zhonghua ULiege; Sergis, N. et al

Poster (2019, June 04)

The main ultraviolet auroral emission at Saturn consists of multiple structures of various sizes forming a discontinuous ring of emissions around Saturn’s poles. For decades, it is known that the main ... [more ▼]

The main ultraviolet auroral emission at Saturn consists of multiple structures of various sizes forming a discontinuous ring of emissions around Saturn’s poles. For decades, it is known that the main emission is occasionally organized in a global spiral surrounding the pole. In August 2016, the Ultraviolet Imaging Spectrograph (UVIS) on board the Cassini spacecraft proceeded to a 7h-long imaging of Saturn’s northern aurora. During this observing sequence, the main emission displayed a spiral wrapping around the pole by more than 370° in longitude. The spiral was in rotation around the pole at ~90% of rigid corotation, which is an unusually high velocity for extended auroral structures. A spiral was again observed during a shorter UVIS sequence, sixteen hours after the end of the first sequence. Simultaneously to the first UVIS sequence, imaging of the energetic neutral atom (ENA) emissions revealed a hot plasma population in the same local time sector as the extremity of the UV spiral. The leading edge of the plasma population follows the spiral structure around the planet. This correspondence suggests that the presence of the hot plasma distorted the magnetospheric current system, resulting in the spiral shape of the main emission. Furthermore, simultaneous in-situ measurements of the ion fluxes exhibit enhancements recurring every ~10.5 hours. The nearly corotating aurora, ENA emissions and ions revealed by this multi-instrument dataset are likely three signatures of a magnetosphere-ionosphere coupling current system and of the associated hot plasma population corotating with the planet. [less ▲]

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See detailNovel HST observations of the Galilean moons Io and Ganymede, and simultaneous Juno-UVS observations of the Io footprint
Roth, Lorenz; Gladstone, G.R.; Hue, V et al

Conference (2019, June)

Within two Hubble Space Telescope (HST) campaigns in support of the NASA Juno mission (GO14634 & GO15638, PI D. Grodent), spectra and spectral images of the moons Io and Ganymede were obtained by HST's ... [more ▼]

Within two Hubble Space Telescope (HST) campaigns in support of the NASA Juno mission (GO14634 & GO15638, PI D. Grodent), spectra and spectral images of the moons Io and Ganymede were obtained by HST's Space Telescope Imaging Spectrograph (STIS) and Cosmic Origins Spectrograph (COS) on several occasions between 2017 and 2019. On one occasion around Juno's perijove #14 in July 2018, the Juno Ultraviolet Spectrograph (UVS) observed Io's footprint simultaneously to the HST imaging of Io. We compare the temporal variability of the local moon aurora and the footprint brightness. Through this comparison, we investigate how the amplitude and phase of the periodically changing brightness of Io's aurora and the footprint are correlated. Additionally, we present results from two novel far-UV observations of Ganymede: High- sensitivity spectra of the moon going into eclipse as well spectral images of the moon while transiting Jupiter. Both Ganymede observations are used to constrain the optical depth of the moon's atmosphere in the far-UV. [less ▲]

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See detailElectron pulsations generated by rotating magnetospheric dynamics at Saturn
Guo, Ruilong ULiege; Yao, Zhonghua ULiege; Sergis, N et al

Poster (2019, June)

Quasi-periodic pulsations of energetic electrons have been frequently observed in Saturn's magnetosphere. The mechanisms for the electron pulsations are far from conclusive, although generally believed to ... [more ▼]

Quasi-periodic pulsations of energetic electrons have been frequently observed in Saturn's magnetosphere. The mechanisms for the electron pulsations are far from conclusive, although generally believed to be associated with field-line resonance due to their similar periodicities. Here we report an electron pulsation event that is related to aurora beads and energetic neutral atom (ENA) emissions. The perturbation of the magnetic field indicates that Cassini spacecraft encountered a series of field-aligned currents (FACs) connected to the aurora beads. The fluxes of energetic electrons were enhanced when the spacecraft crossed the FACs. Both aurora beads and ENA emission were rotating. Given that the FACs interconnect the aurora beads and the active region at equator, a hot plasma population associated with the ENA enhancement, we conclude that the FACs were rotating with Saturn and had finite extent in the azimuthal direction. The periodic features also manifested in the whistler-mode auroral hiss emissions in the same event. We proposed that the electron pulsations we studied are spatial effect of the rotating magnetosphere. The rotation of the whole magnetosphere transfers the spatial effect to the temporal effect, i.e., the pulsation sequences observed by Cassinis multiple instruments. [less ▲]

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See detailSimultaneous Hubble Space Telescope and Juno observations of a jovian auroral enhancement event
Nichols, J.D.; Allegrini, F.; Bagenal, F. et al

Conference (2019, June)

We present concurrent observations of Jupiter's auroras obtained with the Hubble Space Telescope and the planets magnetodisc and M-I coupling currents as observed by the Juno spacecraft, indicating an ... [more ▼]

We present concurrent observations of Jupiter's auroras obtained with the Hubble Space Telescope and the planets magnetodisc and M-I coupling currents as observed by the Juno spacecraft, indicating an association of Jupiter's auroral intensity with current intensity. During PJ11 inbound, Juno measured in the middle magnetosphere a substantial increase in $B_\phi$ from a ‘nominal background of ~2 nT to 7-9 nT between ~30 and 55 R_J, implying increased equatorial radial current flowing as part of the M-I coupling current system associated with the planets auroral emission. During this interval, the $B_\rho$ component was also enhanced from ~10 to ~20 nT, indicating increased azimuthal current and associated radial force balance in the magnetodisc. During this interval of increased radial current, the Hubble Space Telescope observed a simultaneous enhanced intensity of the main emission, peaking at ~2 MR. We compare these observations with the Leicester magnetodisc model, referenced to preliminary Juno JADE plasma data, and the associated theoretical M-I coupling currents. [less ▲]

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See detailObservation of auroral “raindrops” in Jupiter's polar region by Juno-UVS
Hue, Vincent; Greathouse, T.K.; Gladstone, Randy et al

Conference (2019, June)

Juno-UVS has observed Jupiter's FUV auroral emissions during 19 close flybys following Juno orbital insertion on 5 July 2016. Each perijove provides a different snapshot of the Jovian auroral emissions ... [more ▼]

Juno-UVS has observed Jupiter's FUV auroral emissions during 19 close flybys following Juno orbital insertion on 5 July 2016. Each perijove provides a different snapshot of the Jovian auroral emissions recorded at different system III longitude and local time conditions. During PJ6 (19 May 2017), UVS recorded several transient auroral features located within Jupiter's northern polar auroral region. These auroral “raindrops” are characterized by bright spots of H2 emission (typically ~100 kR), which expand into concentric circles over tens of seconds, and seem to appear most often at local times close to noon. In this study we characterize where the raindrops occur in Jupiter's polar region, their spectral characteristics, and their typical expansion rates. [less ▲]

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See detailAre Dawn Storms Jupiter's auroral Substorms?
Bonfond, Bertrand ULiege; Yao, Zhonghua ULiege; Gladstone, R. G. et al

Poster (2019, June)

There are multiple evidences that mass and energy rarely circulate smoothly in planetary magnetospheres. To the contrary, these systems tend to accumulate them until they fall out of balance through ... [more ▼]

There are multiple evidences that mass and energy rarely circulate smoothly in planetary magnetospheres. To the contrary, these systems tend to accumulate them until they fall out of balance through reconfiguration events. The source of mass and the source of energy can differ, as well as the trigger that initiates the collapse. However, despite some fundamental differences between the planets, the auroral signatures of the global reconfigurations bear many similarities that inform us on the common physical processes at play. For the first time, Juno has granted us a complete and global picture of one type of such reconfigurations, the auroral dawn storms, from their initiation to their vanishing. Juno actually captured views of dawn storms at different stages of development in approximately half of the cases. For example, on PJ11 and PJ16, Juno-UVS caught the brief appearence of small elongated spots located poleward of the main emission in the midnight sector. In both cases, a few hours later, the main emission began to brighten and broaden in the same sector. Then the main arc split into two parts, one moving towards the pole and the other moving equatorward. The whole feature also started to rotate towards the dawn sector, progressively accelerating to co-rotation. On PJ6, Juno-UVS observations missed the beginning of the event, but they allowed us to examine the next phase. After the broadening and the splitting of the main emission, the outer arc transformed unto large blobs. During the same time interval, subsequent Hubble Space Telescope images confirmed that the blobs kept on evolving, forming latitudinally extended fingers. All these auroral features resemble auroral morphologies observed at Earth during substorms. The Jovian elongated spots look like terrestrial poleward boundary intensifications (PBIs), the poleward motion of the arc indicates a dipolarisation/current disruption and the blobs in the outer emissions suggest massive plasma injections. [less ▲]

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See detailA study of Local Time Variations of Jupiter’s Ultraviolet Aurora using Juno UVS
Greathouse, T.K.; Gladstone, G.R.; Verteeg, M.H. et al

Poster (2019, June)

With 19 successfully completed Perijoves, Juno UVS has collected an enormous amount of data with unprecedented views of the northern and southern auroras spanning all local time geometries. Juno UVS, with ... [more ▼]

With 19 successfully completed Perijoves, Juno UVS has collected an enormous amount of data with unprecedented views of the northern and southern auroras spanning all local time geometries. Juno UVS, with its spectral and spatial mapping capabilities allows for the retrieval of both UV brightness as well as color ratio information. Maps of both the brightness and color ratio of the main ovals and polar emissions display strong local time variations, some suggestive of ionospheric local time control while others magnetosphere local time drivers. In this presentation we bring together all the UVS observations to date to show and catalogue the many local time phenomena evident therein. [less ▲]

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