Radar evidence of Fe⁺ in a sporadic‐E layer

Incoherent scatter results are presented using compressed‐pulse techniques to study a sporadic‐ E layer at Arecibo. Multiple Barker‐coded pulses were used to obtain the autocorrelation function of the E s layer. A 13‐bit code with a baud length of 4 μsec was employed, resulting in 600‐m height resolution. The observations are examined for the presence of Fe + by least‐square fitting the measured autocorrelation functions to a library of theoretical ones. The analysis indicates that Fe + dominates in the E s layer, usually providing about 70% of the ionization.