Fig. 1From: Dependence of mesospheric Na and Fe distributions on electron density at AreciboAltitudinal and temporal variations of Ne (upper panel), neutral Fe (middle panel), and Na (lower panel) are shown for the night of 17–18 March 2004. Descending C-shaped structures (best seen in the Na distribution) are strong in both Ne and Na but weaker in the case of FeBack to article page