Zakharov simulation study of spectral features of on-demand Langmuir turbulence in an inhomogeneous plasma

Bengt Eliasson, Bo Thidé

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10 Citations (Scopus)

Abstract

We have performed a simulation study of Langmuir turbulence in the Earth's ionosphere by means of a Zakharov model with parameters relevant for the F layer. The model includes dissipative terms to model collisions and Landau damping of the electrons and ions, and a linear density profile, which models the ionospheric plasma inhomogeneity whose length scale is of the order 10–100 km. The injection of energy into the system is modeled by a constant source term in the Zakharov equation. Langmuir turbulence is excited “on-demand” in controlled ionospheric modification experiments where the energy is provided by an HF radio beam injected into the overhead ionospheric plasma. The ensuing turbulence can be studied with radars and in the form of secondary radiation recorded by ground-based receivers. We have analyzed spectral signatures of the turbulence for different sets of parameters and different altitudes relative to the turning point of the linear Langmuir mode where the Langmuir frequency equals the local plasma frequency. By a parametric analysis, we have derived a simple scaling law, which links the spectral width of the turbulent frequency spectrum to the physical parameters in the ionosphere. The scaling law provides a quantitative relation between the physical parameters (temperatures, electron number density, ionospheric length scale, etc.) and the observed frequency spectrum. This law may be useful for interpreting experimental results.
Original languageEnglish
Article numberA02313
Number of pages9
JournalJournal of Geophysical Research: Space Physics
Volume113
Issue numberA2
DOIs
Publication statusPublished - 29 Feb 2008

Keywords

  • langmuir turbulence
  • zakharov simulations
  • plasma inhomogeneity
  • spectral features
  • ionosphere
  • inhomogeneous plasma
  • on-demand Langmuir turbulence

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