Open AccessNumerical modeling of localized electromagnetic waves in the nightside subauroral zone
Author(s) -
Streltsov A. V.,
Mishin E. V.
Publication year - 2003
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 - 10.1029/2003ja009858
Subject(s) - poynting vector , physics , substorm , geophysics , ionosphere , computational physics , magnetosphere , magnetic field , electric field , poynting's theorem , amplitude , alfvén wave , magnetohydrodynamics , optics , quantum mechanics
Results from a numerical study of localized, intense electromagnetic structures observed by the Defense Meteorological Satellite Program (DMSP) satellite F15 in the nightside subauroral zone during the magnetic storm of 6 November 2001 are presented. It is shown that these structures can be interpreted as standing and propagating Alfvén waves generated in the process of ionosphere‐magnetosphere coupling mitigated by the storm and substorm activities. In particular, computations show that when the Pedersen conductivity is low (<1 mho) and a large‐scale electric field in the ionosphere exists, small‐scale irregularities in the E‐layer plasma density can generate Alfvén waves with substantial amplitudes. Initially, perpendicular components of the electric and magnetic fields in those waves are in antiphase and the corresponding Poynting vector is directed along the ambient magnetic field from the ionosphere. As time proceeds, the standing pattern of the resonant Alfvén waves has been developing between the conjugate ionospheres and π/2 phase shift between E ⟂ and B ⟂ appears. At this time the Poynting vector can change direction along the ambient magnetic field several times within one structure. Both types of behaviors of the Poynting vector were observed within localized subauroral electromagnetic structures.