Winfried Otto Schumann and the discovery of the resonances (1952)

Winfried Otto Schumann (1888-1974), professor of electrophysics at the Technical University of Munich (TU München), predicted theoretically in 1952 that the space between the conductive Earth's surface and the conductive ionosphere forms a cavity resonator (waveguide) in which standing electromagnetic waves of extremely low frequencies can be sustained. Schumann 1952

Schumann derived the resonance condition for the Earth-ionosphere cavity and thus obtained order-of-magnitude correct values of the lowest modes. His work provided the theoretical framework that was experimentally confirmed eight years later (see #12). Schumann's name today denotes the entire phenomenon — the global electromagnetic resonances of the Earth-ionosphere cavity excited primarily by lightning activity.

Schumann's student Herbert König developed the measurements further and noted that the lowest (first) mode lies close to a frequency of ~7.8 Hz, that is, in a band close to the alpha rhythm of the human brain. This proximity is a historical note, not proof of any biological effect; the question of a possible influence on humans is examined critically in cluster M.