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Ionospheric dispersion

The term «dispersion» signifies that propagation characteristics differ with frequency. Ionospheric dispersion results from the fact that higher frequencies exhibit lower refractive indices.

Ionospheric dispersion; Higher frequencies exhibit lower refractive indices.

\[n^2 = \epsilon_r = 1-\frac{N{q_e}^2}{\omega^2m_e\epsilon_0}\]

where:
\(n\): the refractive index at a certain point of the ionosphere
\(\epsilon_r\): the relative permittivity at a certain point of the ionosphere
\(N\): the electron density at that point of the ionosphere
\(q_e = 1.602\,176\,6208\cdot10^{-19}\,\text{C}\): the elementary charge of an electron
\(\omega = 2\pi f\): the radial frequency
\(m_e = 9.109\,383\,56\cdot10^{-31}\,\text{kg}\): the mass of an electron
\(\epsilon_0 = \frac{1}{\mu_0 c_0^2}\): the absolute permittivity of free space
\(\mu_0 = 4\pi\cdot10^{-7}\frac{\text{H}}{\text{m}}\): the free space permeability
\(c_0 = 299\,792\,458\,\frac{\text{m}}{\text{s}}\): the speed of light in free space
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