Venus ionospheric clouds: Relationship to the magnetosheath field geometry

Journal Article · Mon Jul 01 00:00:00 EDT 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA01100· OSTI ID:5224586

Ong, M; Luhmann, J G; Russell, C T; Strangeway, R J ^[1]; Brace, L H ^[2]

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1. Univ. of California, Los Angeles (USA)
2. Univ. of Michigan, Ann Arbor (USA)

Venus plasma clouds, apparently detached regions of ionospheric plasma above the main ionosphere of Venus observed by the Langmuir probe on the Pioneer Venus orbiter, are thought to be evidence for bulk removal of ionospheric ions by the solar wind interaction. In an effort to learn more about clouds and their cause(s), the authors analyzed the magnetic field control of cloud positions relative to the planet by rotating their observed locations into a coordinate system in which all of the transverse upstream (interplanetary) magnetic fields were aligned. The results indicate that clouds are scattered around the periphery of the planet in the terminator plane. There is no evidence of a concentration of clouds where the magnetosheath magnetic field is most strongly draped, as suggested by some earlier studies of selected occurrences. On the other hand, statistics show that the change in the orientation of the transverse upstream magnetic field between the inbound and outbound bow shock crossings, for the orbits where clouds are seen, is approximately 30 {degrees} greater than the average upstream change at Venus over the same time intervals. The Spreiter and Stahara gasdynamic model of the magnetosheath provides further support for the idea that a rotation in the upstream transverse magnetic field accompanies cloud formation. Modeling of the magnetic field time series in the magnetosheath for a cloud orbit is possible only when a sequence of upstream fields is used to reconstruct the observed time series.

• OSTI ID: 5224586
• Journal Information: Journal of Geophysical Research; (United States), Vol. 96:A7; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
SOLAR WIND
INTERACTIONS
VENUS PLANET
PLANETARY IONOSPHERES
ELECTRON DENSITY
GEOMETRY
INTERPLANETARY MAGNETIC FIELDS
ION DRIFT
MAGNETOSHEATH
MATHEMATICAL MODELS
MORPHOLOGY
PIONEER SPACE PROBES
MAGNETIC FIELDS
MATHEMATICS
PLANETS
SOLAR ACTIVITY
SPACE VEHICLES
VEHICLES
640107* - Astrophysics & Cosmology- Planetary Phenomena