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Effects of the seasonal asymmetry in ionospheric Pedersen conductance on the appearance of discrete aurora
Author(s) -
Pokhotelov Dimitri,
Lotko William,
Streltsov Anatoly V.
Publication year - 2002
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 - 10.1029/2001gl014010
Subject(s) - ionosphere , physics , electron precipitation , asymmetry , magnetosphere , geophysics , atmospheric sciences , electron , instability , flux (metallurgy) , computational physics , plasma , materials science , mechanics , quantum mechanics , metallurgy
A two‐dimensional numerical two‐fluid MHD model of the coupled magnetosphere‐ionosphere system has been used to examine the effects of seasonal asymmetry in ionospheric conductance on the development of feedback instability and associated energetic electron precipitation. Effects of finite electron inertia and anomalous resistivity in the magnetospheric MHD model lead to the formation of parallel electric fields above the ionosphere as the feedback instability develops. The Fridman‐Lemaire model of energetic electron precipitation has been used to calculate the energy flux carried into the auroral ionosphere by accelerated electrons. The electron energy flux into the lower conductivity winter ionosphere is significantly greater than that into the summer ionosphere due to the asymmetry in ionospheric conductance. The higher energy flux into the winter ionosphere may increase the occurrence of discrete aurora in the winter hemisphere as detected by satellite auroral imaging.