Terrestrial Stationary Waves - Schumann Resonance Hypothesis

Schumann Resonance Hypothesis

It has been suggested this phenomenon arises in the Earth's interior space because of the conductive ionosphere's action as a waveguide. The limited dimensions of the earth cause this waveguide to act as a resonant cavity for electromagnetic waves. The cavity is naturally excited by energy from lightning strikes. The Schumann Resonance is a set of terrestrial stationary waves in the extremely low frequency (ELF) portion of the Earth's electromagnetic field spectrum. Lower frequencies and those at or below longwave bands travel most efficiently as a longitudinal wave and create stationary waves. The ionosphere and the Earth's surface constitute an interface that supports the wave. This resonant cavity is a particular standing wave pattern formed by waves confined in the cavity. The waves correspond to the wavelengths which are reinforced by constructive interference after many reflections from the cavity's reflecting surfaces.

The transfer of electrical energy with small losses in this manner is problematic because the standing wave would occur in the earth-ionosphere cavity, which is too lossy to enable a standing wave of sufficient amplitude to be generated. This limitation is independent of the power of the transmitter. In order for the transmitter to feed power to the receiver as efficiently as it would in a closed low-loss circuit, the power transferred to the receiver should be able to transfer power of the same order of magnitude reciprocally back to the transmitter. This is a necessary condition for the transmitter to “feel” the load connected to the receiver and to supply power to it via the standing wave. In order to do this, the required Q of the earth-ionosphere cavity would have to be on the order of 10^6 or so at the lowest Schumann frequency of about 7.3 Hz. Measurements based on the spectrum of natural electrical radio noise yield a Q of only about 5 to 10.

Regarding this recent notion of power transmission through the earth-ionosphere cavity, a consideration of the earth-ionosphere or concentric spherical shell waveguide propagation parameters as they are known today shows that wireless power transmission by direct excitation of a Schumann cavity resonance mode is not realizable.

The conceptual difficulty with this model is that, at the very low frequencies that Tesla said that he employed (1-50 kHz), earth-ionosphere waveguide excitation, now well understood, would seem to be impossible with the either the Colorado Springs or the Long Island apparatus (at least with the apparatus that is visible in the photographs of these facilities).

Furthermore, the maximum recommended operating frequencies of 25 kHz as specified by Tesla is far above the highest easily observable Schumann resonance mode (the 9th overtone) that exists at approximately 66.4 Hz. Tesla's selection of 25 kHz is wholly inconsistent with the operation of a system that is based upon the direct excitation of a Schumann resonance mode.