Characterization of the Extraterrestrial Magnesium Source in the Atmosphere Using a Meteoric Ablation Simulator

Ablation of Mg from meteoroids entering the Earth's atmosphere was studied experimentally using a Meteoric Ablation Simulator: micron-sized particles of representative meteoritic material were flash heated to simulate atmospheric entry and the ablation rate of Mg with respect to Na measured by fast time-resolved laser-induced fluorescence. Over the range of particle diameters and entry velocities studied, Mg ablates 4.3 ± 2.1 times less efficiently than Na and 2.4 ± 0.8 times less efficiently than Fe. The resulting evaporation profiles indicate that Mg mostly ablates around 84 km in the atmosphere, compared with Fe at 88 km and Na at 95 km. The chemical ablation model Chemical Ablation Model predicts satisfactorily the measured peak ablation altitudes and relative ablated fractions of Mg, Na, Fe, and Ca but does not capture the breadth of the ablation profiles, probably due to the inhomogeneity of the minerals present in meteoroids combined with experimental limitations.©2018. American Geophysical Union. All Rights Reserved.