Observation of radio-wave-induced red hydroxyl emission at low altitude in the ionosphere.

We report the discovery of radio-wave-induced red emission of OH Meinel rotation-vibrational bands at 629.79 nm. These are the first measurements of artificial aurora below 100 km.

The structure of electromagnetic wave-induced 557.7-nm emission associated with a sporadic- E event over arecibo.

We report observations of electromagnetic wave-induced 557.7-nm emission in correspondence with a sporadic low-altitude plasma layer (the sporadic- E layer, E(s)). We show that the structure of 557.