User:IvStewart/Lightning radio

Radio-frequency electromagnetic radiation

Lightning discharges generate radio-frequency electromagnetic waves which can be received thousands of kilometers from their source. The discharge by itself is relatively simple short-lived dipole source that creates a single electromagnetic pulse with a duration of about 1 ms and a wide spectral density. In the absence in the nearby environment of materials with magnetic or electrical interaction properties, at a large distances in a far field zone, the electromagnetic wave will be proportional to the second derivation of the discharge current ^[1]. This is what happens with high-altitude discharges or discharges over areas of a dry land.

A single unaffected discharge over a dry land.

A discharge above conductive ground that induced local Eddy currents.

A discharge above oceanic waters triggered resonance oscillations.

Electromagnetic signals in a 10 Hz to 4 kHz frequency range produced by three different lightning discharges occurring thousands of kilometers away from the same registering station^[2]. The lightning's local environment altered the shape of the received far field signal.

In other cases, the surrounding environment will change the shape of the source signal by absorbing some of its spectrum and converting it into a heat or re-transmitting it back as modified electromagnetic waves ^[3].

^ Landau, Lev D; Lifshitz, Evgeny M (1975). The Classical Theory of Fields. Vol. 2 (4th ed.). Butterworth-Heinemann. ISBN 978-0-7506-2768-9.
^ Issinski, A. (2016-08-28). "Electromagnetic field records taken August 2016 near Stewart BC, Canada".
^ Landau, Lev D; Lifshitz, Evgeny M; Pitaevskii, Lev P (1984). Electrodynamics of Continuous Media. Vol. 8 (2nd ed.). Butterworth-Heinemann. ISBN 978-0-7506-2634-7.

[1] Landau, Lev D; Lifshitz, Evgeny M (1975). The Classical Theory of Fields. Vol. 2 (4th ed.). Butterworth-Heinemann. ISBN 978-0-7506-2768-9.

[2] Issinski, A. (2016-08-28). "Electromagnetic field records taken August 2016 near Stewart BC, Canada".

[3] Landau, Lev D; Lifshitz, Evgeny M; Pitaevskii, Lev P (1984). Electrodynamics of Continuous Media. Vol. 8 (2nd ed.). Butterworth-Heinemann. ISBN 978-0-7506-2634-7.

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