Nature of the iogenic plasma source in Jupiter's magnetosphereII. Near-Io distribution

Smyth, W. H.; Marconi, M. L.

doi:10.1016/j.icarus.2005.01.010

Cited by 17 publications

(20 citation statements)

References 29 publications

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“…Fractional ion abundances (relative to electron densities) are S + / N e ~ 5%, S ++ / N e ~ 20%, S +++ / N e ~ 5%, O + / N e ~ 20%, O ++ / N e ~ 3%, and Σ O n + /Σ S n + ~ 0.8, leaving about 10–15% of the charge as protons and other ions such as Na + and SO 2 + . This composition is similar to that derived from Voyager data by Smith and Strobel [] and by Herbert and Sandel [] but is very different from the Shemansky [] analysis that was also reported in the survey of the Io torus by Bagenal []. The radial profile of ion composition derived from the UV emissions can be matched with the physical chemistry model of Delamere et al [] that assumes a radial profile of neutral O and S atoms (more radially extended than modeled by Smyth and Marconi []). As the densities of both neutrals and plasma decrease with distance from Jupiter, the collision rates sharply decrease with distance.…”

Section: Discussionsupporting

confidence: 75%

Io plasma torus ion composition: Voyager, Galileo, and Cassini

2017

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The Io torus produces ultraviolet emissions diagnostic of plasma conditions. We revisit data sets obtained by the Voyager 1, Galileo, and Cassini missions at Jupiter. With the latest version (8.0) of the CHIANTI atomic database we analyze UV spectra to determine ion composition. We compare ion composition obtained from observations from these three missions with a theoretical model of the physical chemistry of the torus by Delamere et al. (2005). We find ion abundances from the Voyager data similar to the Cassini epoch, consistent with the dissociation and ionization of SO2, but with a slightly higher average ionization state for sulfur, consistent with the higher electron temperature measured by Voyager. This reanalysis of the Voyager data produces a much lower oxygen:sulfur ratio than earlier analysis by Shemansky (1988), which was also reported by Bagenal (1994). We derive fractional ion compositions in the center of the torus to be S+/Ne ~ 5%, S++/Ne ~ 20%, S+++/Ne ~ 5%, O+/Ne ~ 20%, O++/Ne ~ 3%, and Σ(On+)/Σ(Sn+) ~ 0.8, leaving about 10–15% of the charge as protons. The radial profile of ion composition indicates a slightly higher average ionization state, a modest loss of sulfur relative to oxygen, and Σ(On+)/Σ(Sn+) ~ 1.2 at about 8 RJ, beyond which the composition is basically frozen in. The Galileo observations of UV emissions from the torus suggest that the composition in June 1996 may have comprised a lower abundance of oxygen than usual, consistent with observations made at the same time by the EUVE satellite.

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Section: Discussionsupporting

confidence: 75%

Io plasma torus ion composition: Voyager, Galileo, and Cassini

2017

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“… Note . (1) section 3.1and Figures 7 and 8; (2) section 3.2 and Figures 9 and 10; (3) Thomas et al (2004); (4) Smyth and Marconi (2005) and Smith et al (2019); (5) Thomas et al (2004) and Wilson et al (2002); (6) Bagenal (1997), Saur et al (2003), and Dols et al (2008); (7) Saur et al (1998) and Dols et al (2016); (11) Delamere et al (2004). …”

Section: Neutral Cloudsmentioning

confidence: 98%

The Space Environment of Io and Europa

2020

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The Galilean moons play major roles in the giant magnetosphere of Jupiter. At the same time, the magnetospheric particles and fields affect the moons. The impact of magnetospheric ions on the moons' atmospheres supplies clouds of escaping neutral atoms that populate a substantial fraction of their orbits. At the same time, ionization of atoms in the neutral cloud is the primary source of magnetospheric plasma. The stability of this feedback loop depends on the plasma/moon-atmosphere interaction. The purpose of this review is to describe the physical processes that shape the space environment around the two innermost Galilean moons-Io and Europa-and to show their impact from the planet Jupiter out into interplanetary space.

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“…The distribution of molecular SO 2 , SO or S 2 are even harder to detect. Models of the neutral cloud by Smyth and Marconi [2005] estimate the total mass of neutral oxygen and sulfur atoms from Io to comprise ∼52 kt with another ∼17 kt of water products from Europa to total ∼70 kt of neutrals in the Jovian system. The denser neutral cloud at Saturn is more easily observed via UV emissions: of O and H by Cassini UVIS [ Melin et al , 2009; Shemansky et al , 2009] and of OH by Hubble Space Telescope (HST) [ Shemansky et al , 1993].…”

Section: Mass: Distribution Sources and Fluxmentioning

confidence: 99%

Flow of mass and energy in the magnetospheres of Jupiter and Saturn

2011

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[1] We present simple models of the plasma disks surrounding Jupiter and Saturn based on published measurements of plasma properties. We calculate radial profiles of the distribution of plasma mass, pressure, thermal energy density, kinetic energy density, and energy density of the suprathermal ion populations. We estimate the mass outflow rate as well as the net sources and sinks of plasma. We also calculate the total energy budget of the system, estimating the total amount of energy that must be added to the systems at Jupiter and Saturn, though the causal processes are not understood. We find that the more extensive, massive disk of sulfur-and oxygen-dominated plasma requires a total input of 3-16 TW to account for the observed energy density at Jupiter. At Saturn, neutral atoms dominate over the plasma population in the inner magnetosphere, and local source/loss process dominate over radial transport out to 8 R S , but beyond 8-10 R S about 75-630 GW needs to be added to the system to heat the plasma.Citation: Bagenal, F., and P. A. Delamere (2011), Flow of mass and energy in the magnetospheres of Jupiter and Saturn,

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Nature of the iogenic plasma source in Jupiter's magnetosphereII. Near-Io distribution

Cited by 17 publications

References 29 publications

Io plasma torus ion composition: Voyager, Galileo, and Cassini

Io plasma torus ion composition: Voyager, Galileo, and Cassini

The Space Environment of Io and Europa

Flow of mass and energy in the magnetospheres of Jupiter and Saturn

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