A Consideration on Appropriate Parameters for Identifying Electron Density Profile in the Lower Ionosphere by using VLF Wave Propagation in the Earth‐Ionosphere Waveguide

SUMMARY We consider a problem identifying electron density profile in the lower ionosphere by observing electric fields at the Earth's surface in very‐low‐frequency (VLF) band. The identification problem is one of nonlinear inverse problems, and we solve the problem numerically by using the genetic algorithm in this study. The focus of this study is on appropriate parameters to solve the identification problem by using the VLF (22.2 kHz) wave propagating in the earth‐ionosphere waveguide. Numerical results show that the range of the electron density which can be identified is from 107 m‐3 to 108 m‐3, appropriate discretization of the solution space along the altitude is 10 km, and a sufficient number of observation points are necessary to mitigate the effect of noise.