The Structure of Electromagnetic Wave-Induced 557.7-nm Emission Associated with a Sporadic- $\mathit{E}$ 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 557.7-nm emission seen for some events results from a transformation of transmitted energy by ionization clouds, compiling the patchy type $E_s$, and presents a projection of the sporadic- $E$ layer structure on the emission altitude. This allows us to propose the first method for visualizing a horizontal structure of sporadic- $E$ layers.