geocorona
英[dʒɪ(:)əʊkə'rəʊnə]美[ˌdʒioʊkə'roʊnə]
The geocorona is the luminous part of the outermost region of the Earth's atmosphere, the exosphere. It is seen primarily via far-ultraviolet light (Lyman-alpha) from the Sun that is scattered from neutral hydrogen.