Asymmetries in the location of the Venus ionopause

Journal Article · Sun May 01 04:00:00 EDT 1988 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA093iA05p03927· OSTI ID:7194144

Phillips, J L; Luhmann, J G; Knudsen, W C; Brace, L H

Four large data sets of Venus ionopause observations, based on different definitions and observations by Pioneer Venus orbiter field and particle instruments, are compared. Regardless of the definition chosen, the ionopause is observed to be higher on average at dawn than at dusk. The results of an empirical ionosphere model and a data analysis technique which minimizes orbital bias are combined to show that most or all of this asymmetry results from the effects of orbital bias and uneven sampling of solar wind conditions. However, an additional asymmetry is found in which the ionopause is displaced in the direction opposite to the motional electric field of the solar wind. This effect is attributed to asymmetric pickup of exospheric ions by the electric and magnetic fields in the magnetosheath. This ion pickup interpretation can be understood in terms of a previously observed magnetosheath magnetic field asymmetry. Quantitative analysis indicates that the transverse momentum imparted by the solar plasma to pickup particles in their initial gyration is transmitted by the magnetosheath magnetic field to the ionosphere boundary. copyright American Geophysical Union 1988

• Research Organization: Los Alamos National Laboratory, Los Alamos, New Mexico
• OSTI ID: 7194144
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 93:A5; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
CHARGED PARTICLES
ELECTRIC FIELDS
LINEAR MOMENTUM
MAGNETIC FIELDS
PLANETARY IONOSPHERES
PLANETS
PLASMA
PLASMA DENSITY
PLASMA PRESSURE
SOLAR ACTIVITY
SOLAR WIND
TRANSVERSE MOMENTUM
VENUS PLANET