Plasma Waves

Abstract

The interest in wave propagation in plasmas has different roots. One of these was the reflection of electromagnetic waves by the ionosphere [91]. Stimulated by Guglielmo Marconi’s (1874–1937) experiments on long-distance radio in 1901, Oliver Heaviside (1850–1925) [92] and, independently, Arthur Edwin Kennelly (1861–1939) [93] postulated, in 1902, that the Earth’s atmosphere at high altitude must contain an electrically conducting layer that reflects radio waves like a mirror. Many decades before, in 1839, Carl Friedrich Gauss (1777–1855) had conjectured that the fluctuations of the Earth magnetic field might be related to electric currents in the high atmosphere. The quantitative investigation of the ionoshere with radio waves began in the years 1924–1927 with the vertical sounding experiments in the U.S. of Gregory Breit (1899–1981) and Merle Antony Tuve (1901–1982) [94, 95], and in Great-Britain by Edward V. Appleton (1892–1965) [96], which proved the existence of a conducting atmospheric layer, now named the ionosphere, in the altitude regime of (100–500) km. At the same time, Irving Langmuir, at the General Electric Laboratories, discovered high-frequency fluctuations in gas discharges, now known as Langmuir oscillations [97].

“What is the use of a book”, thought Alice, “without pictures or conversations?”

Lewis Carroll, Alice in Wonderland