The magnetic barrier at Venus

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

DOI:https://doi.org/10.1029/91JA00088· OSTI ID:5316798

Zhang, T L; Luhmann, J G; Russell, C T ^[1]

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1. Univ. of California, Los Angeles (USA)

The magnetic barrier at Venus is a region within which the magnetic pressure dominates all other pressure contributions. The barrier is formed in the inner region of the dayside magnetosheath to transfer solar wind momentum flux to the ionosphere. Passes through the dayside magnetosheath and ionopause with Pioneer Venus have allowed us to probe the magnetic barrier directly. These passes have been used to construct altitude profiles of the barrier. Here, the authors define the ionopause as the lower boundary of the barrier. The upper boundary is defined as the altitude where the magnetosheath magnetic pressure is equal to half of the upstream solar wind dynamic pressure corrected by the boundary normal angle. The magnetic barrier is strongest at the subsolar point and weakens as expected with increasing solar zenith angle. The existence of a north-south asymmetry in the barrier strength is also demonstrated. The magnetic barrier is about 200 km thick at the subsolar point and 800 km thick at the terminator, which is comparable with the so-called mantle. They find that the magnetic barrier transfers most of the solar wind dynamic pressure to the ionosphere via the enhanced magnetic pressure. The convected field gasdynamic model is found to predict the correct bow shock location if the magnetic barrier is treated as the obstacle.

• OSTI ID: 5316798
• 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
ALTITUDE
ASYMMETRY
MAGNETOSHEATH
MATHEMATICAL MODELS
MOMENTUM TRANSFER
PIONEER SPACE PROBES
PLANETARY IONOSPHERES
PLASMA PRESSURE
SHOCK WAVES
PLANETS
SOLAR ACTIVITY
SPACE VEHICLES
VEHICLES
640107* - Astrophysics & Cosmology- Planetary Phenomena