Introductory remarks on the classical picture of atmospheric electricity
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The ‘classical picture of atmospheric electricity’ portrays in a simple way, if not too simple a way, a closely knit complex of theories and hypotheses, and perhaps even speculations, centered around the fundamental question of where the electricity of the atmosphere comes from. This picture probably has been accepted with less reservation by the scientific world outside of the narrower circle of scientists active in atmospheric electricity research than by the experts of this circle who alwavs have been aware that the features of this picture never have been really proven by observation, and hardly offer more than a qualitative possibility for an explanation of measuring results. Nevertheless, this concept still represents the best approximation available. The chance that its general validity will be proven in the future is certainly better than 50%. At the same time, contradictions to the classical picture have been found; and it is assumed now that certain modifications of it may be necessary, in particular with respect to short-time averages.
The classical picture is composed of several features which may be listed, vaguely, as follows: spherical capacitor hypothesis for the electrical state in the troposhere, stratosphere, and part of the mesosphere; the ionosphere being (seen from below) an equipotential surface, and forming a Faraday cage; the global thunderstorm activity being the generator charging up the spherical capacitor; atmospheric electric conductivity monotonously increasing with height once the exchange layer is left behind; atmospheric ions, once formed, being stable until recombination. Each of these features consists of a number of elements.
In this paper, the existence of some of the main elements will be investigated; and the significance of measurements and observations leading to the classical picture will be discused. While modifications and alternatives to the classical picture will be the objective of some of the papers to follow during this symposium, some more general additions and, also, some alternatives not likely to be covered later on will be indicated in this introductory paper.
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