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Nonlinear electron heating by resonant shear Alfvén waves in the ionosphere
Author(s) -
Lu J. Y.,
Rankin R.,
Marchand R.,
Tikhonchuk V. T.
Publication year - 2005
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 - 10.1029/2004gl021830
Subject(s) - ionosphere , physics , electron , ionization , atomic physics , plasmasphere , alfvén wave , joule heating , electron density , magnetosphere , magnetohydrodynamics , electron temperature , dissipation , amplitude , geophysics , computational physics , plasma , ion , optics , quantum mechanics , thermodynamics
Ionospheric electron heating by resonant standing shear Alfvén waves in Earth's magnetosphere is investigated. It is demonstrated that in field line resonances (FLRs), electron heating by Alfvén waves produces ionization and large changes in the ionospheric Pedersen conductivity. This leads to a strong feedback effect on the FLR amplitude, along with narrow localization in latitude. Analysis and computer simulations performed with a 2D finite element MHD code, indicate that the primary mechanisms responsible for variations in the electron temperature are ohmic heating by the electron component of the Pedersen current, and electron cooling due to ionization losses and collisions with neutrals. It is shown that electron heating can be quantitatively more important than direct collisional ionization by precipitating electrons. The latter can reduce dissipation losses by at most a factor of two.