geocorona

...There are also hydrogen Lyman lines at 121.6 nm and 102.7 nm, Balmer lines at 656.3 nm, and helium emission lines. These are caused by the resonant scattering of sunlight by hydrogen and helium in the outer atmosphere, and the light is scattered around the night side as a result of multiple scattering, and are sometimes called the geocorona. Looking at the altitude at which night airglow is emitted, they can be broadly divided into those that exist with a thickness of about 10 km centered at altitudes of 85 km to 100 km, those that are distributed at altitudes of 200 km to 400 km, such as some oxygen atom emission lines, and those that are widely distributed from altitudes of 500 km to several thousand km, such as hydrogen and helium emission lines. ...

*Some of the terminology explanations that mention "geocorona" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…また，水素のライマン線121.6nm，102.7nmやバルマー線656.3nmおよびヘリウムの輝線も存在する。これらは外圏大気の水素やヘリウムによって太陽光が共鳴散乱され，多重散乱の結果夜側に光が回りこんだもので，特別に地球コロナgeocoronaと呼ぶことがある。夜間大気光の発光高度をみると，高度85kmから100kmを中心に10kmくらいの厚さで存在するもの，いくつかの酸素原子の輝線のように高度200kmから400kmにかけて分布するもの，水素やヘリウムの輝線のように高度500kmから数千kmにかけて広く分布するものに大別される。…

※「geocorona」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報