Laser-sounding observation of artificially produced lithium in the upper atmosphere - Evidence for ion-neutral interactions

Following a high altitude release of an atomic lithium cloud and its diffusion as Li plus in the atmosphere, a rapid increase in the total lithium content and the appearance of a vertical stratified structure were observed by laser sounding at 670 nm. Results of these observations reveal a flux of neutral lithium of 500/sq cm sec, and a persistent stratification of the lithium boundary, which stratification disappeared in the absence of flux in about 8 h, permitting the lower limit of the turbulent diffusion coefficient to be evaluated as 5,000,000/sq cm sec. The study of the mechanisms explaining the results shows the role of the clustering and recombination processes in alkali photochemistry, and more precisely, in neutral-ion coupling.