Pioneer Venus orbiter magnetic field and plasma observations in the Venus magnetotail

Journal Article · Wed Mar 01 04:00:00 EST 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA03p02383· OSTI ID:5833734

Slavin, J A ^[1]; Intriligator, D S ^[2]; Smith, E J ^[3]

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1. NASA Goddard Space Flight Center, Greenbelt, MD (USA)
2. Carmel Research Center, Santa Monica, CA (USA)
3. California Institute of Technology, Pasadena (USA)

This study uses Pioneer Venus orbiter (PVO) magnetometer and plasma analyzer measurements to investigate the draped-field tail of Venus with an emphasis on determining the magnetic field and plasma conditions within the various tail regions and their dependence upon interplanetary magnetic field (IMF) orientation. For this purpose PVO orbits during which the spacecrafts high inclination trajectory took it through the central magnetotail were identified. Analysis of the observations taken during those orbits indicates that the distribution of plasma within the magnetotail is highly asymmetric and controlled by the orientation of the IMF. In the plasma sheet and adjacent lobe regions downstream of the Venus hemisphere over which the solar wind motional electric field, is directed away from the planet, PVO observed increasing fluxes of H{sup +} and O{sup +} as the spacecraft moves away from the tail axis toward the outer boundary of the tail. No O{sup +} ions were observed outside of the magnetotail based upon the magnetic field data and the definitions adopted in this study. Downstream of the Venus hemisphere over which the solar wind motional electric field is directed in toward the planet, PVO does not usually observe significant fluxes of E/Q = 0-8 kV ions, except sometimes directly adjacent to the outer boundary of the tail. These results are interpreted as being due to the more efficient pick-up of newly ionized atmospheric neutrals over the Venus hemisphere where the initial gyromotion takes the newly created ions away from the dense, lower atmosphere where they might be lost due to scattering (Cloutier et al., 1974). The implications of these findings for the formation and maintenance of the Venus magnetotail are discussed.

• OSTI ID: 5833734
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 94:A3; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
BOUNDARY LAYERS
CATIONS
CHARGED PARTICLES
DATA ANALYSIS
ELECTRIC FIELDS
HYDROGEN IONS
INTERPLANETARY MAGNETIC FIELDS
IONIC COMPOSITION
IONS
LAYERS
MAGNETIC FIELDS
OXYGEN IONS
PLANETARY ATMOSPHERES
PLANETARY MAGNETOSPHERES
PLANETS
PLASMA
PLASMA DENSITY
VENUS PLANET