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The influence of charge exchange on the velocity distribution of hydrogen in the Venus exosphereThe simulation of the exosphere of Venus by a Monte Carlo technique has been extended to provide velocity distribution profiles that can be used with radiative transfer simulation to model the Lyman-alpha emission seen by spacecraft. The line profiles show a narrow core due to the exobase thermal source of hydrogen superimposed on the broad profile of hot hydrogen from charge exchange with hot ions in the nighttime ionosphere. Nightside radial profiles show long tails of upward flowing, escaping atoms. There are some downward and lateral superescape signatures, because the charge exchange source extends well above the exobase. At higher altitudes, flattening and even shallow central valleys appear in the transverse profiles. The planetary average escape rate due to charge exchange was found to be 2.8 x 10 to the 7th/sq cm per s, which is several times larger than escape rates for other candidate mechanisms.
Document ID
19870039731
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hodges, Richard R., Jr.
(Texas Univ. at Dallas Richardson, TX, United States)
Tinsley, Brian A.
(Texas, University Richardson, United States)
Date Acquired
August 13, 2013
Publication Date
December 1, 1986
Publication Information
Publication: Journal of Geophysical Research
Volume: 91
ISSN: 0148-0227
Subject Category
Lunar And Planetary Exploration
Accession Number
87A27005
Funding Number(s)
CONTRACT_GRANT: NGL-44-004-026
CONTRACT_GRANT: NSF ATM-84-04024
Distribution Limits
Public
Copyright
Other

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