Contribution of the cosmic radiation to the ionization of the upper atmosphere

Abstract

On the basis of the earlier measurements of less and Kolhoerster, H. Benndorf (Physik. Zs., v. 27, pp. 686–692, 1926, and Wien‐Harms, Handbuch der Exper. Physik, v. 25‐1, p. 279) considered the effect of the cosmic radiation in producing electrical conductivity in the upper atmosphere. In his theory ions were produced at a rate proportional to the product of the cosmic‐ray intensity by the density of the atmosphere and they disappeared by recombination, the coefficient for which was determined by the theory of J. J. Thomson (Phil. Mag., v. 47, pp. 337–378, 1924). Benndorf concluded that a conductivity 1010 times that at the Earth's surface could be produced by the cosmic radiation at 100 km. The increase was due to a hundred‐fold increase in the cosmic‐ray intensity, accounting for a tenfold increase in the number of free ions and a 109‐fold increase in ionic mobility.