Rocket investigation of the Mg I and Mg II dayglow

The 2800-A dayglow of ionized magnesium in a sporadic E layer was measured by a rocket-borne ultraviolet spectrometer. Because the 2852-A line of neutral magnesium was less than 10 rayleighs while the ionized magnesium emission was measured to be 360 rayleighs, the ratio of Mg+ to Mg was determined to be greater than 22. A model of the ion chemistry in the sporadic E layer shows that neutral magnesium is ionized predominately by the charge transfer reaction with NO+ at a rate greater than 4.1×10−10 or 9.5×10−9 cm3 sec−1 depending on the role MgO2+ plays in the chemistry. In this model, Mg+ is converted back to Mg by radiative recombination.