The Present Status of the Townsend–Huxley Experiment in Theory and Practice

Abstract

Many theoretical investigations have been made of the Townsend–Huxley lateral diffusion experiment but only the most recent have included the spatial variation of the energy distribution function and anisotropic diffusion. Nevertheless, almost without exception, self-consistent and apparently accurate experimental results have been obtained using formulae resulting from these earlier analyses even though, as is now known, these analyses were based on inadequate theoretical foundations. This paradoxical situation has been further confused by the fact that some of the analyses have been based on apparently unrealistic boundary conditions while others have contained an error or a fallacy. A review of the development of the theory up to the present time is given here with the aim of clarifying the position and demonstrating the validity of the data published from a number of laboratories.