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Feasibility study on the derivation of the O + ‐O collision frequency from ionospheric field‐aligned observations
Author(s) -
Dang Tong,
Lei Jiuhou,
Dou Xiankang,
Wan Weixing
Publication year - 2015
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2015ja020987
Subject(s) - collision frequency , thermosphere , ionosphere , physics , momentum (technical analysis) , incoherent scatter , computational physics , ion , atomic physics , atmospheric sciences , geophysics , quantum mechanics , finance , economics
Recently, Vickers et al. (2013) used a simplified ion momentum equation to derive the ion‐neutral (O + ‐O) collision frequency and thermospheric atomic oxygen density from the European Incoherent Scatter Svalbard Radar data. It was assumed that the vertical neutral wind at high latitudes is generally small under geomagnetically quiet conditions so that it was neglected in their derivation. Although the vertical neutral wind may indeed be small, the field‐aligned neutral wind component, which needs to be taken into consideration in the ion momentum equation, can be large. Simulations with the Thermosphere‐Ionosphere Electrodynamics Global Circulation Model have been carried out to evaluate the effect of the neutral wind on the estimation of the ion‐neutral collision frequency from the ion momentum equation. Our results reveal that, even at high latitudes, the effect of the neutral wind can be significant in the derivation of the ion‐neutral collision frequency from ionospheric field‐aligned observations, especially at night.