References of "Radioti, Aikaterini"
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See detailThe energy the auroral electrons in Saturn's atmosphere : remote sensing and thermal consequences
Gérard, Jean-Claude ULg; Gustin, Jacques ULg; Grodent, Denis ULg et al

Poster (2011, October)

Saturn’s north aurora has been observed between January and May 2011 with the Hubble Space Telescope. The objective was to collect spatially resolved spectra at the different local time from dawn to dusk ... [more ▼]

Saturn’s north aurora has been observed between January and May 2011 with the Hubble Space Telescope. The objective was to collect spatially resolved spectra at the different local time from dawn to dusk and compare them with laboratory or synthetic spectra. For this purpose, HST was programmed to slew from mid-latitudes through the auroral oval up to above the limb while collecting data in the timetag mode. The spectra show signatures of absorption by hydrocarbons present above the peak of the auroral emission. The amount of absorption and implications in terms of penetration of the auroral electron beam into Saturn’s atmosphere will be discussed and compared with other determinations of the altitude of the aurora. The effects of the auroral heat import on the thermal structure of the atmosphere both at high and low altitudes will be examined in the light of these results. [less ▲]

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See detailBi-directional electron distributions as tracers for the open-closed field line boundary in Saturn’s magnetosphere
Krupp, Norbert; Radioti, Aikaterini ULg; Roussos, Elias et al

Conference (2011, October)

In this presentation we use bi-directional energetic electron distributions from the MIMI-LEMMS instrument onboard Cassini, auroral observations from the Hubble Space Telescope (HST) and data from the ... [more ▼]

In this presentation we use bi-directional energetic electron distributions from the MIMI-LEMMS instrument onboard Cassini, auroral observations from the Hubble Space Telescope (HST) and data from the UVIS instrument onboard Cassini to characterize the open-closed field line boundary in Saturn’s magnetosphere. The high-latitude open-closed field line boundary at Saturn is thought to be related to the main auroral ring of emission of the planet varying in location, intensity and latitudinal extent as well as in its homogeneity. This study extends the work on the plasmapause/open-closed field line boundary published by [1] by covering a larger data set at different local times and comparing the electron distributions with auroral observations. Based on energetic electron data we characterize the open-closed field line boundary in terms of temporal, local time variations and other parameters and we correlate the Cassini in-situ measurements to the observations of the main auroral ring at Saturn. [less ▲]

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See detailCassini UVIS Observations of Varying Auroral Emissions on Saturn's Night Side
Pryor, W.; Esposito, L.; Jouchoux, A. et al

Poster (2011, July 11)

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See detailAuroral signatures of injections in the magnetosphere of Saturn
Radioti, Aikaterini ULg; Roussos, E.; Grodent, Denis ULg et al

Poster (2011, July 11)

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See detailMapping Jupiter's auroral features to magnetospheric sources: Comparing results from three different models for Jupiter's ionospheric magnetic field
Vogt, M. F.; Kivelson, M. G.; Khurana, K. K. et al

Conference (2011, July 11)

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See detailInside the Jupiter Main Auroral Emissions: Flares, Spots, Arc...and Satellite Footprints?
Bonfond, Bertrand ULg; Vogt, M. F.; Yoneda, M. et al

Conference (2011, July 11)

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See detailThe multiple spots of the Ganymede footprint
Bonfond, Bertrand ULg; Hess, S.; Grodent, Denis ULg et al

Poster (2011, July 11)

Detailed reference viewed: 15 (7 ULg)
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See detailImproved mapping of Jupiter’s auroral features to magnetospheric sources
Vogt, Marissa. F.; Kivelson, Margaret. G.; Khurana, Krishan. K. et al

in Journal of Geophysical Research. Space Physics (2011), 116

The magnetospheric mapping of Jupiter's polar auroral emissions is highly uncertain because global Jovian field models are known to be inaccurate beyond ∼30 RJ. Furthermore, the boundary between open and ... [more ▼]

The magnetospheric mapping of Jupiter's polar auroral emissions is highly uncertain because global Jovian field models are known to be inaccurate beyond ∼30 RJ. Furthermore, the boundary between open and closed flux in the ionosphere is not well defined because, unlike the Earth, the main auroral oval emissions at Jupiter are likely associated with the breakdown of plasma corotation and not the open/closed flux boundary in the polar cap. We have mapped contours of constant radial distance from the magnetic equator to the ionosphere in order to understand how auroral features relate to magnetospheric sources. Instead of following model field lines, we map equatorial regions to the ionosphere by requiring that the magnetic flux in some specified region at the equator equals the magnetic flux in the area to which it maps in the ionosphere. Equating the fluxes in this way allows us to link a given position in the magnetosphere to a position in the ionosphere. We find that the polar auroral active region maps to field lines beyond the dayside magnetopause that can be interpreted as Jupiter's polar cusp; the swirl region maps to lobe field lines on the night side and can be interpreted as Jupiter's polar cap; the dark region spans both open and closed field lines and must be explained by multiple processes. Additionally, we conclude that the flux through most of the area inside the main oval matches the magnetic flux contained in the magnetotail lobes and is probably open to the solar wind. [less ▲]

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See detailJupiter's Aurora as Imaged by the NASA IRTF and Comparison with Hubble Space Telescope Observations in the UV
Lystrup, M.; Radioti, Aikaterini ULg; Bonfond, Bertrand ULg et al

Conference (2011, March)

We investigate Jupiter's infrared aurora using observations from the NASA Infrared Telescope Facility from 1995-2000 as compared with observations in the UV from the Hubble Space Telescope.

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See detailComparative magnetotail flapping: Overview of observations at Earth, Jupiter and Saturn
Volwerk, M.; Andre, N.; Arridge, C. et al

Conference (2011)

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See detailSaturn's aurora seen with the eyes of HST and UVIS
Radioti, Aikaterini ULg

Scientific conference (2011)

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See detailAn overview of the aims and plans of an ISSI Team: Investigating the Dynamics of Planetary Magnetotails
Jackman, C.; Andre, N.; Arridge, C. et al

Poster (2011)

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See detailPeriodic bursts of non-Io DAM and its relationship to Jovian aurora phenomena
Rucker, H.; Panchenko, M.; Grodent, Denis ULg et al

Poster (2011)

Detailed reference viewed: 4 (0 ULg)
See detailComparative Planetary Magnetotails
Bagenal, F.; Jackman, C.; Slavin, J. et al

Poster (2011)

Detailed reference viewed: 7 (0 ULg)
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See detailSmall-scale structures in Saturn's ultraviolet aurora
Grodent, Denis ULg; Gustin, Jacques ULg; Gérard, Jean-Claude ULg et al

in Journal of Geophysical Research. Space Physics (2011), 116

On 26 August 2008, the Ultraviolet Imaging Spectrograph Subsystem (UVIS) instrument onboard the Cassini spacecraft recorded a series of spatially resolved spectra of the northern auroral region of Saturn ... [more ▼]

On 26 August 2008, the Ultraviolet Imaging Spectrograph Subsystem (UVIS) instrument onboard the Cassini spacecraft recorded a series of spatially resolved spectra of the northern auroral region of Saturn. Near periapsis, the spacecraft was only five Saturn radii (R[SUB]S[/SUB]) from the surface and spatially resolved auroral structures as small as 500 km across (0.5° of latitude). We report the observation of two types of UV auroral substructures at the location of the main ring of emission, bunches of spots and narrow arcs. They are found in the noon and dusk sectors, respectively, at latitudes ranging from 73 to 80° corresponding to equatorial regions located beyond 16 R[SUB]S[/SUB]. Their brightness ranges from 1 to 30 kR and their characteristic size varies from 500 km to several thousands of km. These small-scale substructures are likely associated with patterns of upward field aligned currents resulting from nonuniform plasma flow in the equatorial plane. It is suggested that magnetopause Kelvin-Helmholtz waves trigger localized perturbations in the flow, like vortices, able to give rise to the observed UV auroral substructures. [less ▲]

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See detailBifurcations of the main auroral ring at Saturn: ionospheric signatures of consecutive reconnection events at the magnetopause
Radioti, Aikaterini ULg; Grodent, Denis ULg; Gérard, Jean-Claude ULg et al

in Journal of Geophysical Research. Space Physics (2011), 116

This work reports for the first time on bifurcations of the main auroral ring at Saturn observed with the UVIS instrument onboard Cassini. The observation sequence starts with an intensification on the ... [more ▼]

This work reports for the first time on bifurcations of the main auroral ring at Saturn observed with the UVIS instrument onboard Cassini. The observation sequence starts with an intensification on the main oval, close to noon, which is possibly associated with dayside reconnection. Consecutive bifurcations appear with the onset of dayside reconnection, between 11 and 18 magnetic local time, while the area poleward of the main emission expands to lower latitudes. The bifurcations depart with time from the main ring of emission, which is related to the open-closed field line boundary. The augmentation of the area poleward of the main emission following its expansion is balanced by the area occupied by the bifurcations, suggesting that these auroral features represent the amount of newly open flux and could be related to consecutive reconnection events at the flank of the magnetopause. The observations show that the open flux along the sequence increases when bifurcations appear. Magnetopause reconnection can lead to significant augmentation of the open flux within a couple of days and each reconnection event opens ∼10% of the flux contained within the polar cap. Additionally, the observations imply an overall length of the reconnection line of ∼4 hours of local time and suggest that dayside reconnection at Saturn can occur at several positions on the magnetopause consecutively or simultaneously. [less ▲]

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See detailQuasi-periodic polar flares at Jupiter: A signature of pulsed dayside reconnections?
Bonfond, Bertrand ULg; Vogt, M. F.; Gérard, Jean-Claude ULg et al

in Geophysical Research Letters (2011), 38

The most dynamic part of the Jovian UV aurora is located inside the main auroral oval. This region is known to regularly show localized but dramatic enhancements on timescales of several tens of seconds ... [more ▼]

The most dynamic part of the Jovian UV aurora is located inside the main auroral oval. This region is known to regularly show localized but dramatic enhancements on timescales of several tens of seconds, called polar flares. They have often been associated with the polar cusp, based on their location in the polar cap. The present study is based on the longest high-time resolution image sequences ever acquired by the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. We report the first observations of a regularity in the occurrence of these flares, with a timescale of 2-3 minutes. We use a magnetic flux mapping model to identify the region corresponding to these emissions in the equatorial plane: the radial distance ranges from 55 to 120 Jovian radii and the local times are between 10: 00 and 18: 00. The analogy with similar phenomena observed at Earth suggests that these quasi-periodic auroral flares could be related to pulsed reconnections at the dayside magnetopause. Indeed, the flares' projected location in the equatorial plane and their rate of re-occurrence show some similarities with the properties of the flux transfer events observed by the Pioneer and Voyager probes. [less ▲]

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