UV Io footprint leading spot: A key feature for understanding the UV Io footprint multiplicity?

Bonfond, Bertrand; Grodent, Denis; Gérard, Jean‐Claude; Radioti, Aikaterini; Saur, Joachim; Jacobsen, Sven

doi:10.1029/2007gl032418

Cited by 97 publications

(151 citation statements)

References 13 publications

Supporting

Mentioning

140

Contrasting

Order By: Relevance

“…The interspot angular separation observed in the IR is $ 5 3 (Connerney and Satoh, 2000). UV observations show that the interspot distance may vary with the position of Io relative to the torus center, with an average value of $ 6 3 (Gé rard et al, 2006;Bonfond et al, 2008Bonfond et al, , 2009 Fig. 2).…”

Section: Multiple Arcsmentioning

confidence: 94%

“…These footprint signatures are generally composed of several spots (see Fig. 2a and Gé rard et al, 2006;Bonfond et al, 2008). UV observations have led to classify these spots as: (i) the main Alfvé n wing spot (MAW) which has in average the lowest lead angle and marks the position of the Alfvé n waves arriving directly from Io; (ii) secondary reflected Alfvé n wing spots (RAW) resulting from Alfvé n wave reflections within the Io plasma torus prior to their escape to high latitudes; (iii) a third kind of spot, named the transhemispheric electron beam (TEB) spot, thought to be generated by electrons accelerated at high latitude in the antiplanetward direction in one hemisphere and hence precipitating in the opposite hemisphere .…”

Section: Article In Pressmentioning

confidence: 98%

See 1 more Smart Citation

Lead angles and emitting electron energies of Io-controlled decameter radio arcs

Hess

Петин

Zarka

et al. 2010

Planetary and Space Science

Self Cite

View full text Add to dashboard Cite

a b s t r a c tThe Io-controlled radio arcs are emissions in the decametric radio range which appear arc shaped in the time-frequency plane. Their occurrence is controlled by Io's position, so it has been for long inferred that they are powered by the Io-Jupiter electrodynamic interaction. Their frequency ranges correspond to the electron cyclotron frequencies along the Io Flux tube, so they are expected to be generated by cyclotron maser instability (CMI). The arc shape was proposed to be a consequence of the strong anisotropy of the decametric radio emissions beaming, combined with the topology of the magnetic field in the source and the observation geometry. Recent papers succeeded at reproducing the morphologies of a few typical radio arcs by modeling in three dimensions the observation geometry, using the best available magnetic field model and a beaming angle variation consistent with a loss-cone driven CMI. In the continuation of these studies, we present here the systematic modeling of a larger number of observations of the radio arcs emitted in Jupiter's southern hemisphere (including multiple arcs or arcs exhibiting abrupt changes of shape), which permits to obtain a statistical determination of the emitting field line localization (lead angle) relative to the instantaneous Io field line, and of the emitting particle velocities or energies. Variations of these parameters relative to Io's longitude are also measured and compared to the location of the UV footprints of the Io-Jupiter interaction. It is shown that the data are better organized in a reference frame attached to the UV spot resulting from the main Alfvé n wing resulting from the Io-Jupiter interaction. It is proposed that the radio arcs are related to the first reflected Alfvé n wing rather than to the main one.

show abstract

Section: Multiple Arcsmentioning

confidence: 94%

Section: Article In Pressmentioning

confidence: 98%

Lead angles and emitting electron energies of Io-controlled decameter radio arcs

Hess

Петин

Zarka

et al. 2010

Planetary and Space Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…The other half forms transhemispheric electron beams (TEB) precipitating in the opposite hemisphere. In the Io interaction case, an UV spot is associated to these beams [Bonfond et al, 2008]. These TEB spots are distinct from the MAW spot in the Io case due to the variations of the MAW lead angle with respect to the Io longitude.…”

Section: Particle Accelerationmentioning

confidence: 99%

Comparative study of the power transferred from satellite-magnetosphere interactions to auroral emissions

et al. 2011

View full text Add to dashboard Cite

[1] Io's interaction with the Jovian magnetosphere generates a power of about 10 12 W which propagates as Alfvén waves along the magnetic field lines and is partly transferred to electrons, resulting in intense auroral emissions. A recent study of the power transmission along the Io flux tube and of the electron acceleration at high latitudes showed that the power of the observed emissions is well explained by assuming filamentation of the Alfvén waves in the torus and the acceleration of the electrons at high latitude. At Jupiter, UV footprints related to Europa and Ganymede have also been observed. At Saturn recent observations revealed a weak UV footprint of Enceladus. We apply the Io interaction model to the Europa and Enceladus interactions. We show that the Alfvén wave filamentation leads to a precipitating electron power consistent with the power of the observed UV footprints.Citation: Hess, S. L. G., P. A. Delamere, V. Dols, and L. C. Ray (2011), Comparative study of the power transferred from satellite-magnetosphere interactions to auroral emissions,

show abstract

“…The location of the different spots varies with the System III longitude of Io, that is, its position in the plasma torus (Bonfond et al, 2008(Bonfond et al, , 2009Gérard et al, 2006). Three different types of spots have been characterized by Bonfond et al (2008Bonfond et al ( , 2013 and Hess et al (2010Hess et al ( , 2013: (1) The main Alfvén wing (MAW) spot is generally the brightest feature and is located at the foot of the direct Alfvén wing connecting Io to Jupiter's ionosphere; (2) the reflected Alfvén wing (RAW) spot comes from the waves that have bounced from the opposite hemisphere; and (3) there is also a transhemispheric electron beam (TEB) spot that is generated by electron beams that are accelerated by the Alfvén waves in the MAW but travel along the magnetic field away from the ionosphere above the MAW spot and into the opposite hemisphere. This mechanism also explains the bidirectional electron beams observed downstream of Io by Williams et al (1999) and Frank and Patterson (1999).…”

Section: Introductionmentioning

confidence: 99%

Alfvén Wave Propagation in the Io Plasma Torus

Hinton

Bagenal

Bonfond

2019

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

Io, the most volcanically active body in the solar system, fuels a plasma torus around Jupiter with dissociation products of SO2 at a rate of ~1,000 kg/s. We use a combination of in situ Voyager 1 data and Cassini Ultraviolet Imaging Spectrograph observations to constrain a diffusive equilibrium model of the Io plasma torus. The interaction of the Io plasma torus with Io launches Alfvén waves in both directions along magnetic field lines. We use the recent Juno‐based JRM09 magnetic field model combined with our 3‐D model of the Io plasma torus to simulate the propagation of Alfvén waves from the moon to the ionosphere of Jupiter. We map the location of multiple reflections of iogenic Alfvén waves between the northern and southern hemispheres. The location of the first few bounces of the Alfvén wave pattern match the Io auroral footprints observed by the Hubble Space Telescope.

show abstract

UV Io footprint leading spot: A key feature for understanding the UV Io footprint multiplicity?

Cited by 97 publications

References 13 publications

Lead angles and emitting electron energies of Io-controlled decameter radio arcs

Lead angles and emitting electron energies of Io-controlled decameter radio arcs

Comparative study of the power transferred from satellite-magnetosphere interactions to auroral emissions

Alfvén Wave Propagation in the Io Plasma Torus

Contact Info

Product

Resources

About