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dc.contributor.authorBhattacharya, Tapas
dc.date.accessioned2022-03-23T19:04:53Z
dc.date.available2022-03-23T19:04:53Z
dc.date.issued2009-05
dc.identifier.urihttp://hdl.handle.net/11122/12833
dc.descriptionThesis (M.S.) University of Alaska Fairbanks, 2009en_US
dc.description.abstract"The object of this work is to determine the diffusion coefficient (D) of trimethylaluminum (TMA) in the lower thermosphere as a function of altitude (h). This is done by measuring the dispersion of chemiluminescent TMA that is released in discrete quantities, or puffs, from sounding rockets at altitudes 120 to 180 km. Diffusing TMA, which glows in contact with atmospheric oxygen, is observed with stereoscopic ground-based imaging. Brightness profiles across a puff are found to be Gaussian in shape, with width parameter [sigma](t, h) that increases with age (t) of the puff leading to D = [sigma]² (t, h)/2t, independent of time, which is in good agreement with some past results. For example D = (2.5 ± 0.2) x 10³m²s⁻¹ at an altitude of 128 km for the state of the thermosphere at that time. A constant A links three altitude-dependent terms, the diffusion coefficient, temperature and density, at a particular location of the atmosphere, via D(h) = ATS (h)/n(h). It is determined from this study to be A=(4.42±0.05)x10¹⁸(m·s)⁻¹ for s = 0.75. Using these values for A and s, and temperatures and the densities determined from the MSIS-90 thermospheric model, diffusion coefficients for TMA can be determined at other locations and under different geomagnetic conditions"--Leaf iiien_US
dc.language.isoen_USen_US
dc.subjectThermosphereen_US
dc.subjectThermospheric windsen_US
dc.titleDetermination of the diffusion coefficient for trimethylaluminum in the thermosphere at altitudes 120 to 180 kmen_US
dc.typeThesisen_US
dc.type.degreemsen_US
dc.identifier.departmentDepartment of Physicsen_US
refterms.dateFOA2022-03-23T19:04:54Z


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