First-time observations of E-region artificial green-line emission over Arecibo

Summary form only given. Heater-induced E-region 557.7 nm emission over Arecibo (Puerto Rico) was observed for the first time by the Cornell University CCD camera on 22 and 26 January, 1998. An analysis of the optical, ISR and ionosounder data shows that (1) the green-line emission comes from the E-region altitude and is in a close connection with a sporadic-E layer near 121-124 km altitude; (2) the structure of the 557.7-nm emission cloud results from a heater energy transformation by the sporadic-E layer and reflects the sporadic-E layer structure; and (3) the heater-induced green-line emission may be used as a method for visualization of a horizontal structure of a natural sporadic E layer inside the area illuminated by the heater beam. The sporadic layers in the ionosphere E region are found to be an important component of several national space weather programs because of its significance for ground based transmissions and navigational use