Open AccessDamping standing Alfvén waves in the magnetosphere
Author(s) -
Southwood David J.,
Kivelson Margaret G.
Publication year - 2001
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000ja000343
Subject(s) - wkb approximation , physics , ionosphere , magnetosphere , alfvén wave , limit (mathematics) , field line , quantum electrodynamics , field (mathematics) , phase (matter) , computational physics , classical mechanics , geophysics , magnetic field , magnetohydrodynamics , mathematical analysis , quantum mechanics , mathematics , pure mathematics
Using the WKB approximation, we analyze the phase and energy structure of damped Alfvén wave structures in a magnetospheric field configuration. In the WKB limit the real part of the eigenfrequency is determined by the field line length while the damping rate is determined by the ionospheric conductivity. Expressions are worked linking the damping decrement to the ionospheric damping, and it is shown that the damping effect of each ionosphere adds linearly to the damping decrement. We end with a critique of the use of the WKB solution for Alfvénic wave structures and indicate where such solutions may be unreliable.