Bow shock studies at Mercury, Venus, Earth, and Mars with applications to the solar-planetary interaction problem
A series of bow shock studies conducted for the purpose of investigating the interaction between the solar wind and the terrestrial planets is presented. Toward this end appropriate modeling techniques have been developed and applied to the bow wave observations at Venus, Earth, and Mars. For Mercury the measurements are so few in number that no accurate determination of shock shape was deemed possible. Flow solutions generated using the observed bow wave surface as a boundary condition in a single fluid variable obstacle shape gasdynamic model produced excellent fits to the measured width and shape of the earth's magnetosheath. This result and the observed ordering of shock shape and position by upstream sonic Mach number provide strong support for the validity of the gasdynamic approximation. At Mercury the application of earth type models to the individual Mariner 10 boundry crossings has led to the determination of an effective planetary magnetic moment of 6+-2 x 10/sup 22/ G-cm/sup 3/. Consistent with the presence of a small terrestrial style magnetosphere, southward interplanetary magnetic fields were found to significantly reduce the solar wind stand-off distance most probably through the effects of dayside magnetic reconnection. For Venus the low altitude solar wind flow field derived from gasdynamic modeling of bow shock location and shape indicates that a fraction of the incident streamlines are absorbed by the neutral atmosphere near the ionopause; approximately 1% and 8%, respectively, in the solar maximum Pioneer Venus and solar minimum Venera measurements. Accordingly, it appears that cometary processes must be included in model calculations of the solar wind flow about Venus. At Mars the moderate height of the gasdynamic solar wind-obstacle interface and the weakness of the Martian ionosphere/atmosphere are found to be incompatible with a Venus type interaction.
- Research Organization:
- California Univ., Los Angeles (USA)
- OSTI ID:
- 6084361
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
PLANETARY MAGNETOSPHERES
SHOCK WAVES
SOLAR WIND
EARTH PLANET
INTERPLANETARY MAGNETIC FIELDS
MAGNETOSHEATH
MAGNETOSPHERE
MARS PLANET
MATHEMATICAL MODELS
MERCURY PLANET
PLANETARY IONOSPHERES
VENUS PLANET
ATMOSPHERES
EARTH ATMOSPHERE
MAGNETIC FIELDS
PLANETARY ATMOSPHERES
PLANETS
SOLAR ACTIVITY
640107* - Astrophysics & Cosmology- Planetary Phenomena