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Blowoff of an atmosphere and possible application to Io
Author(s) -
Hunten Donald M.
Publication year - 1985
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl012i005p00271
Subject(s) - exosphere , atmosphere (unit) , diffusion , drag , flux (metallurgy) , eddy diffusion , physics , limit (mathematics) , mechanics , atmospheric sciences , environmental science , meteorology , thermodynamics , materials science , turbulence , ion , mathematics , mathematical analysis , quantum mechanics , metallurgy
Diffusion equations for two components are set up with mutual drag terms included. It is found that these terms become important when the flux of an escaping gas is of the order of its diffusion limit. In this situation, other gases can be dragged along (blowoff) and both scale heights tend towards equality. It appears that this may occur on Io, giving a strong tendency to equalize the scale heights of O, S, and SO 2 without any appeal to eddy diffusion. Ionic bombardment of the exosphere may therefore eject material with an O:S ratio approaching 2, rather than the much higher value expected for a diffusively separated atmosphere. Future aeronomical studies of this atmosphere should include the drag terms in the diffusion equations.