The Design of the Electric Field in a Van de Graaff Generator

The paper discusses the best proportions for the high-voltage electrodes in a Van de Graaff generator. The criterion used is that the maximum field strength on the electrode surfaces should be as low as possible. It is shown that there is an optimum design, but that the proportions are by no means critical. A method is developed for calculating field strengths in an axially symmetrical electrode system from the known field distribution in an axial section, the concept of ¿stress multiplication factors¿ being introduced for this purpose. Stress multiplication factors are then derived for a number of field boundaries common in Van de Graaff generators.