Io'S Atmospheric Freeze-Out Dynamics In The Presence Of A Non-Condensable Species

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dc.contributor.utaustinauthorMoore, C. H.en
dc.contributor.utaustinauthorGoldstein, D. B.en
dc.contributor.utaustinauthorVarghese, P. L.en
dc.contributor.utaustinauthorTrafton, L. M.en
dc.contributor.utaustinauthorStewart, B. D.en
dc.contributor.utaustinauthorWalker, A. C.en
dc.creatorMoore, C. H.en
dc.creatorGoldstein, D. B.en
dc.creatorVarghese, P. L.en
dc.creatorTrafton, L. M.en
dc.creatorStewart, B. D.en
dc.creatorWalker, A. C.en
dc.date.accessioned2015-04-16T14:48:14Zen
dc.date.available2015-04-16T14:48:14Zen
dc.date.issued2009-12en
dc.description.abstractOne dimensional direct simulation Monte Carlo (DSMC) simulations are used to examine the effect of a trace non-condensable species on the freeze-out dynamics of Io's sulfur dioxide sublimation atmosphere during eclipse and egress. Due to finite ballistic times, essentially no collapse occurs during the first 10 minutes of eclipse at altitudes above similar to 100 km, and hence immediately after ingress auroral emission morphology above 100 km should resemble that of the immediate pre-eclipse state. In the absence of a non-condensable species the sublimation SO2 atmosphere will freeze-out (collapse) during eclipse as the surface temperature drops. However, rapid collapse is prevented by the presence of even a small amount of a perfect non-condensable species due to the formation of a static diffusion layer several mean free paths thick near the surface. The higher the non-condensable mole fraction, the longer the collapse time. The effect of a weakly condensable gas species (non-zero sticking/reaction coefficient) was examined since real gas species may not be perfectly non-condensable at realistic surface temperatures. It is found that even a small sticking coefficient dramatically reduces the effect of the diffusion layer on the dynamics. If the sticking coefficient of the non-condensable exceeds similar to 0.25 the collapse dynamics are effectively the same as if there was no non-condensable present. This sensitivity results because the loss of non-condensable to the surface reduces the effective diffusion layer size and the formation of an effective diffusion layer requires that the layer be stationary which does not occur if the surface is a sink. As the surface temperature increases during egress from eclipse the sublimating SO2 gas pushes the non-condensable diffusion layer up to higher altitudes once it becomes dense enough to be collisional. This vertical species stratification should alter the auroral emissions after egress.en
dc.description.departmentAerospace Engineeringen
dc.identifier.citationChris H. Moore, David B. Goldstein, Philip L. Varghese, Laurence M. Trafton, Bénédicte D. Stewart, and Andrew C. Walker. AIP Conference Proceedings 1084, 1079 (Dec., 2008); doi: 10.1063/1.3076442en
dc.identifier.doi10.1063/1.3076442en
dc.identifier.issn0094-243Xen
dc.identifier.issn978-0-7354-0615-5en
dc.identifier.urihttp://hdl.handle.net/2152/29478en
dc.language.isoEnglishen
dc.relation.ispartofserialRarefied Gas Dynamicsen_US
dc.rightsAdministrative deposit of works to UT Digital Repository: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en
dc.subjectioen
dc.subjectatmospheric collapseen
dc.subjectdiffusion layeren
dc.subjectnoncondensable gasen
dc.subjectvolcanic plumesen
dc.subjectvapor flowsen
dc.subjectsublimationen
dc.subjectradiationen
dc.subjecteclipseen
dc.subjectmodelen
dc.subjectengineering, aerospaceen
dc.subjectphysics, fluids & plasmasen
dc.titleIo'S Atmospheric Freeze-Out Dynamics In The Presence Of A Non-Condensable Speciesen
dc.typeArticleen

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