Solar wind interaction with the ionosphere of Venus inferred from radio scintillation measurements

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

DOI:https://doi.org/10.1029/JA094iA02p01473· OSTI ID:5916414

Woo, R; Sjogren, W L; Kliore, A J ^[1]; Luhmann, J G ^[2]; Brace, L H ^[3]

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1. California Institute of Technology, Pasadena (USA)
2. Univ. of California, Los Angeles (USA)
3. NASA Goddard Space Flight Center, Greenbelt, MD (USA)

This paper presents the first S-band (2.3 GHz) radio scintillations observed in the ionosphere of Venus and discovered when the Pioneer Venus Orbiter spacecraft traversed the ionosphere of Venus. In situ plasma measurements as well as propagation calculations confirm that the scintillations are caused by electron density irregularities in the topside ionosphere of Venus below the ionopause. While these topside plasma irregularities have not been studied before, simultaneous magnetic field measurements presented here reveal that they are associated with the penetration of large-scale magnetic fields in the ionosphere. Previous studies based on extensive magnetic field measurements have shown that the presence of large-scale magnetic fields occurs in the subsolar region when the solar wind dynamic pressure exceeds the ionospheric plasma pressure. As with the large-scale magnetic fields, the disturbed plasma and resulting scintillations are therefore a manifestation of high-dynamic solar wind interaction with the ionosphere. Since the scintillations only occur in the subsolar region of Venus, the global morphology of ionospheric scintillations at Venus is different from that of the terrestrial ionosphere, where scintillations are observed in both polar and equatorial regions, with peaks occurring during nighttime. This difference apparently stems from the fact that Venus is not a magnetic planet. The authors also demonstrate that the disturbed plasma produced by the high-dynamic solar wind interaction can be remotely sensed by scintillations during radio occultation measurements, that is, when the spacecraft is outside the ionosphere.

• OSTI ID: 5916414
• Journal Information: Journal of Geophysical Research; (USA), Vol. 94:A2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
PLANETARY IONOSPHERES
SOLAR WIND
INTERACTIONS
VENUS PLANET
DYNAMICS
ELECTRON DENSITY
MAGNETIC FIELDS
MARS PLANET
RADIOWAVE RADIATION
SCINTILLATIONS
SOLAR CYCLE
ELECTROMAGNETIC RADIATION
MECHANICS
PLANETS
RADIATIONS
SOLAR ACTIVITY
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena