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  2. Schumann resonances - Wikipedia

    en.wikipedia.org/wiki/Schumann_resonances

    The global electromagnetic resonance phenomenon is named after physicist Winfried Otto Schumann who predicted it mathematically in 1952. Schumann resonances are the principal background in the part of the electromagnetic spectrum [2] from 3 Hz through 60 Hz [3] and appear as distinct peaks at extremely low frequencies around 7.83 Hz (fundamental), 14.3, 20.8, 27.3, and 33.8 Hz.

  3. Extremely low frequency - Wikipedia

    en.wikipedia.org/wiki/Extremely_low_frequency

    The fundamental Schumann resonance is at approximately 7.83 Hz, the frequency at which the wavelength equals the circumference of the Earth, and higher harmonics occur at 14.1, 20.3, 26.4, and 32.4 Hz, etc. Lightning strikes excite these resonances, causing the Earth–ionosphere cavity to "ring" like a bell, resulting in a peak in the noise ...

  4. Radio atmospheric signal - Wikipedia

    en.wikipedia.org/wiki/Radio_atmospheric_signal

    A frequency vs. time plot (spectrogram) showing several whistler signals amidst a background of sferics as received at Palmer Station, Antarctica on August 24, 2005.A radio atmospheric signal or sferic (sometimes also spelled "spheric") is a broadband electromagnetic impulse that occurs as a result of natural atmospheric lightning discharges.

  5. File:Schumann resonance animation.ogv - Wikipedia

    en.wikipedia.org/wiki/File:Schumann_resonance...

    Original file (Ogg Theora video file, length 24 s, 1,280 × 720 pixels, 7.01 Mbps, file size: 20.08 MB) This is a file from the Wikimedia Commons . Information from its description page there is shown below.

  6. Radio propagation - Wikipedia

    en.wikipedia.org/wiki/Radio_propagation

    Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]

  7. Winfried Otto Schumann - Wikipedia

    en.wikipedia.org/wiki/Winfried_Otto_Schumann

    Winfried Otto Schumann (May 20, 1888 – September 22, 1974) was a German physicist and electrical engineer who predicted the Schumann resonances, a series of low-frequency resonances caused by lightning discharges in the atmosphere.

  8. Ionosphere - Wikipedia

    en.wikipedia.org/wiki/Ionosphere

    Main gases of the ionosphere (about 50 km; 31 miand above on this chart) vary considerably by altitude. The F layer or region, also known as the Appleton–Barnett layer, extends from about 150 km (93 mi) to more than 500 km (310 mi) above the surface of Earth. It is the layer with the highest electron density, which implies signals penetrating ...

  9. Electromagnetically induced transparency - Wikipedia

    en.wikipedia.org/wiki/Electromagnetically...

    An intense "coupling" laser drives the | | transition at detuning above resonance. Due to the quantum interference of transition amplitudes, a weaker "cooling" laser driving the | g → | e {\displaystyle |g\rangle \rightarrow |e\rangle } transition at detuning Δ g {\displaystyle \Delta _{g}} above resonance sees a Fano-like feature on the ...