Atomic hydrogen in the upper atmosphere of earth /Z equal to or greater than 100 km/

The role of hydrogen in the origin and evolution of the terrestrial atmosphere is studied. Hydrogen concentration, atomic hydrogen in the exosphere, solar activity effects are some of the fields discussed, stressing the discrepancy between theoretical and experimental values concerning the escape flux measurements. The study of hydrogen in the thermosphere and the effect of the polar wind are also considered. The development of a highly sensitive mass spectrometer to be installed on a satellite is suggested as a tool for better understanding the correlation between atomic hydrogen and the upper atmosphere through exact measurements.