geocorona


Also found in: Dictionary, Wikipedia.
Related to geocorona: Lagrangian point

geocorona

(jee-oh-kŏ-roh -nă) A tenuous cloud of hydrogen and some helium extending more than 50 000 km from the Earth's outermost atmospheric layer to the magnetosphere. It scatters Lyman-alpha radiation (see Lyman series) from the Sun, producing a glow that is visible on long-distance far-ultraviolet photographs of the Earth. It also interferes with far-ultraviolet astronomical observations from Earth orbit.

geocorona

[¦jē·ō·kə′rō·nə]
(geophysics)
The outermost part of the earth's atmosphere, consisting of extremely attenuated hydrogen extending to perhaps 15 earth radii, that emits Lyman-alpha radiation under the action of sunlight.
References in periodicals archive ?
"We were not aware of it until we dusted off observations made over two decades ago by the SOHO spacecraft." Around the area where Earth's atmosphere merges into outer space is a cloud of hydrogen atoms called the geocorona. During the research, SWAN, one of the space instruments, was able to trace the hydrogen signature and tell us how exactly far the outskirts of the geocorona go.
It includes the plasmasphere, ring currents, and the geocorona effect, which is a glow that results when hydrogen atoms absorb ultraviolet light from the Sun and reemit the light (at 121.6 nm).
From its polar orbit, IMAGE will create comprehensive snapshots of Earth's auroral ovals, geocorona, ring currents, magnetosphere, and plasma environment every 5 minutes.