Communities and Collections

Precipitation and nonlinear effects in geomagnetic field line resonancesournal of Geophysical Research: Space Physics, 108(A4), [pp

  • Author(s) / Creator(s)
  • The structure of auroral arcs sustained by field line resonances (FLRs) is determined using a model that describes the interplay between ionospheric feedback, nonlinear, and dispersive effects in a curvilinear geomagnetic topology. The model includes modulation of Pedersen conductance by hundreds of eV electrons that precipitate in the ionosphere through the action of shear Alfven wave field-aligned currents (FACs). The competition between ionospheric feedback dissipation, wave dispersion, and nonlinearity results in large-amplitude, long-period oscillations of the FAC, and in emission of slow-moving small-scale secondary auroral arcs and density perturbations. Using observed values of nightside conductivities and realistic topology of geomagnetic field lines, we obtain FLRs with frequencies in the range of a few mHz, spatial scales up to several km near the ionosphere, and FAC amplitudes extending to tens of muA/m(2). Our model explains the excitation of structured auroral arcs in regions of low ionospheric conductance.

  • Date created
  • Subjects / Keywords
  • Type of Item
    Article (Published)
  • DOI
  • License
    © 2003 American Geophysical Union. This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited.
  • Language
  • Citation for previous publication
    • Prakash, M., Rankin, Robert, & Tikhonchuk, V. T. (2003). Precipitation and nonlinear effects in geomagnetic field line resonances. Journal of Geophysical Research: Space Physics, 108(A4), [pp. 1-11].
  • Link to related item