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Title: Magnesium chemistry in the upper atmosphere of Earth and Mars
Author: Whalley, Charlotte Louise
ISNI:       0000 0004 2718 2019
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2011
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Ablation of cosmic dust causes the deposition of metals into the upper atmospheres of Earth and Mars between 80 -120 km. Magnesium is one of the most abundant metals in this dust and large concentrations have been observed in the terrestrial atmosphere. Kinetic measurements have been made of the reactions of Mg- and Mg+- containing species with relevant atmospheric constituents using a pulsed laser photolysis-laser induced fluorescence technique and a fast flow tube. The resulting rate coefficients were then input into a 1-dimensional atmospheric model in order to test them against mid-latitude satellite observations of the Mg and Mg+ layers. The model was able to replicate the main observations such as peak concentration, peak height, Mg depletion and seasonal variation. In the Martian atmosphere radio occultation measurements have observed a third sporadic layer of electrons. It has been suggested that this electron layer could indicate a layer of Fe+ and Mg+ ions in analogy with the terrestrial atmosphere. However, it would be expected that in the CO2-rich Martian atmosphere metal ions would be rapidly neutralised. Experimental studies of the effectiveness of CO2 as a third-body in pressure dependant Mg+ reactions were undertaken in a PLP-L1F system. These measurements were combined with the rate coefficients measured in the earlier work to model the lifetime of metal ions within the atmosphere of Mars. The model was able to replicate the observations and found the sporadic third layer to consist mainly of Mg+.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available