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Erosion of Galilean satellite surfaces by Jovian magnetosphere particlesThe effects on the surfaces of the Galilean satellites Europa, Ganymede and Callisto of impacts by particles of the Jupiter magnetosphere in which they are immersed are estimated. Differential ion fluxes measured by the Voyager low-energy magnetosphere particle analyzer as a function of ion energy were used to calculate ice erosion fluxes for the satellites under the assumption that each is 50% ice covered. Calculations were performed on the basis of laboratory data concerning the ice sputtering coefficients of protons and oxygen ions of various energies. A water erosion rate of greater than 10 to the 10th/sq cm per sec is obtained for Europa, which implies a total erosion over 1 billion years of an ice layer 100 m deep. Atmospheric column densities of the H2O molecules sputtered from the surface but not escaping the satellites are also calculated for the three satellites assuming a sputtered ion temperature of 2000 K, and are found to dominate those produced by sublimation. Finally, estimates are presented of the source and loss processes for an oxygen atmosphere around Ganymede created by sputtering or sublimation.
Document ID
19810051588
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Johnson, R. E.
(Virginia, University Charlottesville, Va., United States)
Lanzerotti, L. J.
(Virginia Univ. Charlottesville, VA, United States)
Brown, W. L.
(Bell Telephone Laboratories, Inc. Murray Hill, N.J., United States)
Armstrong, T. P.
(Kansas, University Lawrence, Kan., United States)
Date Acquired
August 11, 2013
Publication Date
May 29, 1981
Publication Information
Publication: Science
Volume: 212
Subject Category
Lunar And Planetary Exploration
Accession Number
81A35992
Funding Number(s)
CONTRACT_GRANT: NSF AST-79-12690
CONTRACT_GRANT: NASA TASK 1
CONTRACT_GRANT: N00024-78-C-5384
Distribution Limits
Public
Copyright
Other

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