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Evidence of anisotropic temperatures of molecular ions in the auroral ionsphere
Author(s) -
Lathuillere C.,
Hubert D.,
La Hoz C.,
Kofman W.
Publication year - 1991
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 - 10.1029/90gl02584
Subject(s) - anisotropy , ion , incoherent scatter , spectral line , computational physics , range (aeronautics) , electric field , line (geometry) , physics , line of sight , atomic physics , materials science , geophysics , optics , ionosphere , astrophysics , geometry , astronomy , mathematics , quantum mechanics , composite material
Using incoherent scatter measurements obtained from Kiruna and Sodankylä EISCAT remote stations, and corresponding to different aspect angles, we show, for the first time, anisotropic temperatures of molecular ions. The electric field obtained for the 5 hours period of the 2nd February 1990 experiment presented here range from 20 to 50 mV/m. We show that the line of sight ion temperature deduced from Kiruna incoherent scatter spectra is larger than the one deduced from Sodankylä spectra which correspond to a smaller aspect angle. A statistical approach has been chosen to evaluate a β s parameter for Sodankylä measurements which describes the anisotropy. We found a value of 0.60 ± 0.02 which compares very well with values inferred from theoretical studies.