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Variations of hot O in the thermosphere
Author(s) -
Oliver W. L.,
Schoendorf J.
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900612
Subject(s) - thermosphere , solstice , atmospheric sciences , altitude (triangle) , atmosphere (unit) , solar maximum , solar minimum , ionosphere , hot atom , physics , environmental science , atomic physics , solar cycle , latitude , meteorology , plasma , astronomy , solar wind , geometry , mathematics , quantum mechanics
Using measurements of electron temperature and density, a model of neutral density, and a theoretical expression for the O + −O collision cross section, we compute the ion temperature and find it to be lower than the measured value. We compute the amount of hot O at 4000°K necessary to provide this heat deficit. At 400 km altitude very little hot O is needed at solar maximum while 1–2% of total O must be hot at solar maximum. Hot O densities at 400 km altitude are lowest during the day, highest at night; lowest at the equinoxes, highest at the solstices; lowest at solar maximum, highest at solar minimum; lowest for magnetically disturbed periods, highest for quiet periods; lowest for a warm, dense thermosphere, highest for a cool, rare thermosphere. All of these variations are consistent with thermal quenching by ambient O, with larger ambient O densities yielding lower hot O densities. This indicates that hot O should form a layer shape in the atmosphere.