Venus: An Upper Limit on Intrinsic Magnetic Dipole Moment Based on Absence of a Radiation Belt

Allen, J. A. Van; Krimgis, S. M.; Frank, L. A.; Armstrong, T. P.

doi:10.1126/science.158.3809.1673

Cited by 20 publications

(2 citation statements)

References 42 publications

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“…The Mariner 2, 5, and 10 spacecraft that passed near Venus did not directly cross the nightside (solar wind shadow) region of the planet. The charged particle measurements in general showed no influence of Venus [e.g., Frank et al, 1963;Van Allen et al, 1967;Simpson et al, 1974]. It would be of great interest to measure the spatial dependence, in the equatorial plane across the nightside of Venus, of a low energy solar energetic particle event in order to study the type of shadowing examined here for Titan.…”

Section: Plotted Inmentioning

confidence: 99%

Effects of Titan on trapped particles in Saturn's magnetosphere

Maclennan¹,

Lanzerotti²,

Krimigis³

et al. 1982

J. Geophys. Res.

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The close fly‐by of the Voyager 1 spacecraft to the Saturnian satellite Titan provided an opportunity for the low energy charged particle (LECP) experiment to investigate the influences of Titan on the magnetosphere energetic particle distributions. Magnetic field data from the magnetometer (MAG) experiment are used with angular distribution data from LECP to study the changes in the pitch angle distributions of ions (40 < Ei < 220 keV), and electrons (26 < Ee < 61 ReV). Before and after the Titan encounter the ions are observed to exhibit a bulk motion in the direction expected of corotation of the particles with the planetary magnetic field. The magnetosphere corotation velocity outside the influence of Titan is deduced to be ∼100 to 150 km/s, less than the ∼200 km/s expected for rigid corotation. Titan appears to disrupt the corotation motion of the ions: the fluxes of ions in the corotation direction are appreciably diminished in intensity, while those observed in the equatorial plane perpendicular to this direction are relatively unaffected. The resulting distribution and trajectory modeling conclusions suggest that the convection electric field is effectively absent in the wake of Titan. Before and after the Titan encounter the electrons are observed to exhibit pitch angle distributions peaked at ∼90°, representative of trapped particles. The presence of Titan produces a reduction in the fluxes of the electrons and flatter distributions with pitch angle.

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Section: Plotted Inmentioning

confidence: 99%

Effects of Titan on trapped particles in Saturn's magnetosphere

Maclennan¹,

Lanzerotti²,

Krimigis³

et al. 1982

J. Geophys. Res.

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“…Between these two lobes of stretched-out magnetic field and the bow shock exists the magnetosheath, where the slowed-down plasma gets accelerated back again to the pre-shocked solar wind velocity. However, as Venus has no intrinsic magnetic field ( Van Allen et al 1967;Russell et al 1981;Phillips & Russell 1987), the normal to the current sheet is only dependent on the upstream IMF direction as a consequence of field line draping, rather than having a preferred direction in a planet based inertial frame. Just as in the case of the Earth's magnetotail, this structure shows a wide range of activity, with: magnetic reconnection having been observed (Volwerk et al 2009(Volwerk et al , 2010Zhang et al 2010) as well as magnetotail flapping (Vörös et al 2008b;Rong et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Solar Orbiter’s first Venus flyby

Volwerk

Horbury

Woodham

et al. 2021

A&A

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Context. The induced magnetosphere of Venus is caused by the interaction of the solar wind and embedded interplanetary magnetic field with the exosphere and ionosphere of Venus. Solar Orbiter entered Venus’s magnetotail far downstream, > 70 Venus radii, of the planet and exited the magnetosphere over the north pole. This offered a unique view of the system over distances that had only been flown through before by three other missions, Mariner 10, Galileo, and BepiColombo. Aims. In this study, we study the large-scale structure and activity of the induced magnetosphere as well as the high-frequency plasma waves both in the magnetosphere and in a limited region upstream of the planet where interaction with Venus’s exosphere is expected. Methods. The large-scale structure of the magnetosphere was studied with low-pass filtered data and identified events are investigated with a minimum variance analysis as well as combined with plasma data. The high-frequency plasma waves were studied with spectral analysis. Results. We find that Venus’s magnetotail is very active during the Solar Orbiter flyby. Structures such as flux ropes and reconnection sites were encountered, in addition to a strong overdraping of the magnetic field downstream of the bow shock and planet. High-frequency plasma waves (up to six times the local proton cyclotron frequency) are observed in the magnetotail, which are identified as Doppler-shifted proton cyclotron waves, whereas in the upstream solar wind, these waves appear just below the proton cyclotron frequency (as expected) but are very patchy. The bow shock is quasi-perpendicular, however, expected mirror mode activity is not found directly behind it; instead, there is strong cyclotron wave power. This is most likely caused by the relatively low plasma-β behind the bow shock. Much further downstream, magnetic hole or mirror mode structures are identified in the magnetosheath.

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The Magnetosheath and Magnetotail of Venus

Phillips¹,

McComas²

1991

Venus Aeronomy

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Venus: An Upper Limit on Intrinsic Magnetic Dipole Moment Based on Absence of a Radiation Belt

Cited by 20 publications

References 42 publications

Effects of Titan on trapped particles in Saturn's magnetosphere

Effects of Titan on trapped particles in Saturn's magnetosphere

Solar Orbiter’s first Venus flyby

The Magnetosheath and Magnetotail of Venus

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