Io and its plasma environment

Southwood, D. J.; Kivelson, M. G.; Walker, Raymond J.; Slavin, J. A.

doi:10.1029/ja085ia11p05959

Cited by 124 publications

(66 citation statements)

References 32 publications

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“…In the Jovian system the AW was first discussed for Io (Goldreich and Lynden-Bell, 1969;Neubauer, 1980;Southwood et al, 1980;Herbert, 1985;Wright and Southwood, 1987;Chust et al, 2005), and the analysis was later expanded to describe the interaction of other Galilean satellites, in particular Europa (Neubauer, 1998(Neubauer, , 1999Khurana and Kivelson, 1999;Volwerk et al, 1999). The properties of the AWs, such as the AW angle θ A , can be useful in determining the local plasma density of the surrounding medium (Neubauer, 1980) if no direct measurements are available.…”

Section: Introductionmentioning

confidence: 99%

Europa's Alfvén wing: shrinkage and displacement influenced by an induced magnetic field

2007

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Abstract. The Galileo magnetometer data are used to investigate the structure of the Alfvén wing during three flybys of Europa. The presence of an induced magnetic field is shown to shrink the cross section of the Alfvén wing and offset it along the direction radial to Jupiter. Both the shrinkage and the offset depend on the strength of the induced field. The entry and exit points of the spacecraft into and out of the Alfvén wings are modeled to determine the angle between the wings and the background magnetic field. Tracing of the Alfvén characteristics in a model magnetic field consisting of Jupiter's background field and an induced field in Europa produces an offset and shrinking of the Alfvén wing consistent with the geometric modeling. Thus we believe that the Alfvén wing properties have been determined correctly. The Alfvén wing angle is directly proportional to the local Alfvén velocity, and is thus a probe for the local plasma density. We show that the inferred plasma density can be understood in terms of the electron density measured by the plasma wave experiment. When Europa is located in the Jovian plasma sheet the derived mass-per-charge exceeds the previous estimates, which is a result of increased pickup of sputtered ions near the moon. The estimated rate of O + 2 pickup agrees well with the results from numerical models.

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Section: Introductionmentioning

confidence: 99%

Europa's Alfvén wing: shrinkage and displacement influenced by an induced magnetic field

2007

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“…Southwood et al (1980) examined data from several Voyager instruments and examined the possible role of an intrinsic magnetic field for Io as a way t o retain a robust enough ionosphere, which could provide enough conductivity for completing the Io-Jupiter current circuit. Neubauer (1980) presented an analytical model of the AlfvGn standing wave current system which connects current through the ionosphere of Io.…”

Section: Introductionmentioning

confidence: 99%

Effects of kinetic processes in shaping Io's global plasma environment: A 3D hybrid model

Lipatov

Combi

2006

Icarus

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Abstract. The global dynamics of the ionized and neutral components in the environment of Io plays an important role in the interaction of Jupiter's corotating magnetospheric plasma with Io. The stationary simulation of this problem was done in the MHD and the electrodynamics approaches. One of the main significant results from the simplified two-fluid model simulations (Saur et al., 2002) was a production of the structure of the doublepeak in the magnetic field signature of the I O flyby that could not be explained by standard MHD models. In this paper, we develop a method of kinetic ion simulation. This method employs the fluid description for electrons and neutrals whereas for ions multilevel, drift-kinetic and particle, approaches are used. We also take into account charge-exchange and photoionization processes. Our model provides much more accurate description for ion dynamics and allows us to take into account the realistic anisotropic ion distribution that cannot be done in fluid simulations. The first results of such simulation of the dynamics of ions in the Io's environment are discussed in this paper.

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“…It has been shown that the contribution of mass-loading to the plasma currents in the interaction can be equivalently described as a Pedersen conductance (Neubauer 1998a;Hill and Pontius 1998). The Alfvén wing model mentioned above originally was applied to the sub-Alfvénic (M A < 1) interaction between Io and its plasma torus (Goertz 1980;Neubauer 1980;Southwood et al 1980), but it also can be applied to the interactions of the flowing plasma with other moons that have ionospheres and/or a source of neutrals. Even if the flow is superAlfvénic (M A > 1) but sub-magnetosonic (M ms < 1), as for ambient conditions at Titan's orbit, the Alfvén wing model remains a valid description of the interaction.…”

Section: External Sources: Plasma Interaction With Moonsmentioning

confidence: 98%

Magnetic Fields of the Satellites of Jupiter and Saturn

et al. 2009

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This paper reviews the present state of knowledge about the magnetic fields and the plasma interactions associated with the major satellites of Jupiter and Saturn. As revealed by the data from a number of spacecraft in the two planetary systems, the magnetic properties of the Jovian and Saturnian satellites are extremely diverse. As the only case of a strongly magnetized moon, Ganymede possesses an intrinsic magnetic field that forms a mini-magnetosphere surrounding the moon. Moons that contain interior regions of high electrical conductivity, such as Europa and Callisto, generate induced magnetic fields through electromagnetic induction in response to time-varying external fields. Moons that are non-magnetized also can generate magnetic field perturbations through plasma interactions if they possess substantial neutral sources. Unmagnetized moons that lack significant sources of neutrals act as absorbing obstacles to the ambient plasma flow and appear to generate field perturbations mainly in their wake regions. Because the magnetic field in the vicinity of the moons contains contributions from the inevitable electromagnetic interactions between these satellites and the ubiquitous plasma that flows onto them, our knowledge of the magnetic fields intrinsic to these satellites relies heavily on our understanding of the plasma interactions with them.

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Io and its plasma environment

Cited by 124 publications

References 32 publications

Europa's Alfvén wing: shrinkage and displacement influenced by an induced magnetic field

Europa's Alfvén wing: shrinkage and displacement influenced by an induced magnetic field

Effects of kinetic processes in shaping Io's global plasma environment: A 3D hybrid model

Magnetic Fields of the Satellites of Jupiter and Saturn

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