Interplanetary magnetic field effects on the interaction of the solar wind with Venus
The solar-wind interaction with Venus are examined, with emphasis on the role of the interplanetary magnetic field (IMF), using observations from Pioneer Venus Orbiter (PVO). The intrinsic magnetic field of Venus is much smaller than that of Earth. Based on a survey of low-altitude PVO magnetometer observations, the planetary magnetic moment is less than 8.4 x 10/sup 10/Tm/sup 3/, or roughly 1/100,000 of the terrestrial moment. As a result, the impact of changing IMF orientation on the interaction is very different at Venus than at the magnetized planets. The solar plasma interacts directly with the ionospheric plasma, which generally is able to maintain a shielding current system which constitutes an impenetrable boundary. This ionopause has an average subsolar altitude of roughly 300 km, increasing to approx. 900 km near the terminator, and is consistently higher in the dawn hemisphere than in the dusk hemisphere. This observed asymmetry is shown to results from flow aberration due to planetary motion and from orbital bias. The IMF is compressed and draped around the boundary, reaching a maximum strength just above the ionopause. This field can in certain circumstances enter the ionosphere and be carried downward by ionospheric convection. In the magnetosheath, the region between the ionosphere and the bow shock, the magnetic field has a characteristic draping pattern.
- Research Organization:
- California Univ., Los Angeles (USA)
- OSTI ID:
- 7059092
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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