On the Estimation of the Ionospheric Exit Regions of Magnetospheric VLF Radio Waves by the Use of Wave Energy Distribution in Wave Number Space

  • S. Shimakura
  • M. Hayakawa


A new ground-based direction finding technique is proposed to estimate the ionospheric exit regions of magnetospheric VLF waves on the basis of wave energy distribution of those waves in wave number space which is evaluated by means of maximum entropy concept. This method is essentially different from the previous direction finding techniques by which the wave normal direction of an equivalent plane wave can be estimated. The solution by maximum entropy method, however, depends on the inversion model, or on the wave polarization included in the integration kernels, because TE- and TM-mode waves can independently propagate in free space. In this paper, the effectiveness and dependence of maximum entropy solutions on the inversion model are discussed for the investigation of the ionospheric transmission and magnetospheric propagation mechanisms of magnetospheric VLF waves.


Maximum Entropy Method Polarization Model Inversion Model Spectral Matrix Wave Number Space 


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Copyright information

© Springer-Verlag Tokyo 1991

Authors and Affiliations

  • S. Shimakura
    • 1
  • M. Hayakawa
    • 2
  1. 1.Department of Electrical EngineeringChiba UniversityChibaJapan
  2. 2.Research Institute of AtmosphericsNagoya UniversityAichiJapan

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