Day-time ionospheric reflection of LF waves - Numerical analysis of simple models

The sensitivity of low-frequency (LF) waves to changes in ionospheric properties is used to advantage in a method analyzing experimental LF propagation data. The real part of the complex refractive index is important in numerical calculations of ionospheric reflection coefficients on the basis of simple models of electron density distributions, while the imaginary part is important in numerical full-wave calculations, particularly in dealing with propagation of 60 kHz waves. The behavior of the real and imaginary parts of the index in the neighborhoods of 60 kHz, 70 kHz, and 80 kHz is studied and contrasted. The imaginary part is shown to be a very regular function of the electron density and collision frequency.