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geocorona
geocorona n.
Brit. 
/ˌdʒiːə(ʊ)kəˈrəʊnə/
, /ˌdʒiːə(ʊ)kəˈrəʊnə/U.S. /ˌdʒioʊkəˈroʊnə/
Atmospheric Physics a luminous and extremely tenuous region at the outer limit of the exosphere, consisting chiefly of ionized hydrogen and extending to approx. fifteen earth radii; also called protonosphere./ˌdʒioʊkəˈroʊnə/ΘΚΠ
the world > the earth > weather and the atmosphere > [noun] > layer of gas surrounding earth
geocorona1959
1959 I. S. Shklovsky in Planetary & Space Sci. 1 64/1 Even if the observed diffuse Lα radiation should be accounted for by some reason other than the interplanetary gas, e.g. by a ‘geocorona’ extending over several thousands of kilometers..then [etc.].
1984 Science 13 July 175/3 The most intense emission is the resonance scattering of solar photons by hydrogen atoms in the geocorona.
2009 M. C. Kelley Earth's Ionosphere (ed. 2) v. 224 Since hydrogen atoms and molecules can escape the earth's gravitational field, the earth is surrounded with a hydrogen gas ‘geocorona’.
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