Physics and chemistry of the ionosphere

Abstract The ionosphere is the part of the upper atmosphere where free electrons exist in sufficient concentrations to affect the propagation of radio waves. This paper introduces the science of the ionosphere and reviews the experimental techniques used in its study (Sections 1–3); the average behaviour of the ionosphere and some of its notable anomalies are described in Section 4. In the lower part of the ionosphere, between heights of about 60 and 250 km, the distribution of electrons is almost entirely governed by the production and recombination processes (Sections 5–7). The movement of ionization by winds, electric fields and diffusion produces some interesting phenomena at heights above 100 km, and mainly governs the electron distribution at heights above 250 km (Sections 8–10). Finally, ionospheric storms and other problems are touched upon in Sections 11–12.