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Structure and dynamics of the ionosphereThe structure of the Venus ionosphere and the major processes occurring within it are summarized. The daytime ionosphere is created by solar EUV radiation incident on the thermosphere; it is in photochemical equilibrium near its peak at about 142 km, where O2(+) is the major ion, and near diffusive equilibrium in its upper regions, where the major ion is O(+). The day-to-night plasma pressure gradient across the terminator drives a nightward ion flow which, together with electron precipitation, contributes to the formation of the nighttime ionosphere. Large-scale radial holes or plasma depletions extending downwards to nearly the ionization peak in the antisolar region are also observed which are associated with regions of strong radial magnetic fields. The ionopause is a highly dynamic and complex surface, extending from an average altitude of 290 km at the subsolar point to about 1000 km at the terminator and from 200 to over 3000 km on the nightside. A variety of solar wind interaction products are observed in the mantle, a transition region between the ionospheric plasma and the flowing shocked solar wind.
Document ID
19820041952
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Nagy, A. F. (Michigan, University Ann Arbor, MI, United States)
Brace, L. H. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 10, 2013
Publication Date
March 4, 1982
Publication Information
Publication: Nature
Volume: 296
Subject Category
LUNAR AND PLANETARY EXPLORATION
Distribution Limits
Public
Copyright
Other