From "UNLESS PEACE COMES - A Scientific Forecase of New Weapons" 1968 Nigel Calder ed. Chapter: "Geophysical warefare, How to wreck the environment," by GJF MacDonald, UCLA Asc. Director of the Institute of Geophysics and Planetary Physics BRAIN WAVES ROUND THE WORLD? At heights of forty to fifty kilometres above the Earth.s surface, substantial numbers of charged particles are found which make this part of the atmosphere, the ionosphere, a good conductor of electricity. The rocks and oceans are also more conducting than the lower atmosphere. Thus, we live in an insulating atmosphere between two spherical conducting shells or, as the radio engineer would put it, in an Earth-ionosphere cavity, or waveguide. Radio waves striking either conducting shell tend to be reflected back into the cavity, and this phenomenon is what makes conventional long-distance radio communication possible. Only recently, however, has there been any interest in natural electrical resonances within the Earth-ionosphere waveguide. Like any such cavity, the Earth-ionosphere waveguide will tend to sustain radio oscillation at certain frequencies in preference to others. These resonant frequencies are primarily determined by the size of the Earth and the speed of light, but the properties of the ionosphere modify them to a certain extent. The lowest resonances begin at about eight cycles per second, far below the frequencies ordinarily used for radio communication. Because of their long wavelength and small field strength, they are difficult to detect. Moreover, they die down quickly, within 1/16 second or so; in engineering terms, the cavity has a short time constant. The natural resonant oscillations are excited by lightning strokes, cloud-to-ground strokes being a much more efficient source than horizontal cloud-to-cloud discharges. On the average, about 100 lightning strokes occur each second (primarily concentrated in the equatorial regions) so that normally about six lightning flashes are available to introduce energy before a particular oscillation dies down. A typical oscillation.s field strength is of the order of 0.3 millivolts per metre. The power of the oscillations varies geographically. For example, for a source located on the equator in Brazil the maximum intensity of the oscillation is near the source and at the opposite side of the Earth (around Indonesia). The intensity is lower in intermediate regions and towards the poles. One can imagine several ways in which to increase the intensity of such electrical oscillations. The number of lightning strokes per second could be enhanced by artificially increasing their original number. Substantial progress has been made in the understanding of the physics of lightning and of how it might be controlled. The natural oscillations are excited by randomly occurring strokes. The excitation of timed strokes would enhance the efficiency with which energy is injected into an oscillation. Furthermore, the time constant of the oscillation would be doubled by a four-fold increase in the electrical conductivity of the ionosphere, so that any scheme for enhancing that conductivity (for example, by injecting readily ionized vapour) lowers the energy losses and lengthens the time constant, which would permit a greater number of phased lightaing strokes before the decay of an oscillation. The enhanced low-frequency electrical oscillations in the Earth-ionosphere cavity relate to possible weapons systems through a little understood aspect of brain physiology. Electrical activity in the brain is concentrated at certain frequencies, some of it extremely slow, a little around five cycles per second, and very conspicuous activity (the so-called alpha rhythm) around ten cycles per second. Some experiments have been done in the use of a flickering light to pull the brain.s alpha rhythm into unnatural synchrony with it; the visual stimulation leads to electrical stimulation. There has also been work on direct electrical driving of the brain. In experiments discussed by Norbert Wiener, a sheet of tin is suspended from the ceiling and connected to a generator working at ten cycles per second. With large field strengths of one or two volts per centimetre oscillating at the alpha-rhythm frequency, decidedly unpleasant sensations are noted by human subjects. The Brain Research Institute of the University of California is investigating the effect of weak oscillating fields on human behaviour. The field strengths in these experiments are of the order of a few hundredths of a volt per centimetre. Subjects show small but measurable degradation in performance when exposed to oscillating fields for periods of up to fifteen minutes. The field strengths in these experiments are still much stronger, by a factor of about 1,000, than the observed natural oscillations in the Earth-ionosphere cavity. However, as previously noted, the intensity of the natural fluctuations could bc increased substantially and in principle could be maintained for a long time, as tropical thunder storms are always available for manipulation. The proper geographical location of the source of lightning, coupled with accurately-timed, artificially-excited strokes, could lead to a pattern of oscillations that produced relatively high power levels over certain regions of the Earth and substantially lower levels over other regions. In this way, one could develop a system that would seriously impair brain performance in very large populations in selected regions over an extended period. The scheme I have suggested is admittedly far-fetched, but I have used it to indicate the rather subtle connections between variations in man.s environmental conditions and his behaviour. Perturbation of the environment can produce changes in behaviour patterns. Since our understanding of both behavioural and environmental manipulation is rudimentary, schemes of behavioural alteration on the surface seem unrealistic. No matter how deeply disturbing the thought of using the environment to manipulate behaviour for national advantage is to some, the technology permitting such use will very probably develop within the next few decades.