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Atomic nitrogen abundance in polar upper thermosphere
Author(s) -
Sivjee G. G.
Publication year - 1983
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/gl010i004p00349
Subject(s) - thermosphere , daytime , nitrogen , polar , atmospheric sciences , cusp (singularity) , electron , electron density , physics , line (geometry) , atomic physics , electron temperature , electron precipitation , ionosphere , environmental science , geophysics , plasma , astronomy , magnetosphere , geometry , mathematics , quantum mechanics
In night‐time auroras the intensity of highly excited (n ⩾ 3) NI line emissions is much less than 1% of the red and near‐IR N 2 1PG as well as N 2 +M Δv = 3 band emissions, while in mid‐day cusp auroras the ratio is greater than 10%. These observations point to electron impact on N (rather than on N 2 ) as the main source of some of the mid‐day auroral NI line emissions. To produce the measured level of NI 6945‐51 and 6979‐82A emissions, by cusp electrons impacting on N, requires the daytime polar thermospheric density of atomic nitrogen, above 200 km, in excess of 10 7 cm −3 .