Ionisation of the Kennelly-Heaviside Layer

Abstract

THE eclipse observations of August 31, 1932, and Appleton's Tromsø observations, indicate fairly certainly that the normal daytime ionisation in the E layer (100 km. height) is due mainly to solar wave radiation, and not to neutral corpuscles as Chapman suggested. But the ionising wave radiation may not be ultra-violet light (in amount corresponding to Planck's formula at the sun's temperature) as now generally supposed. As Eckersley has remarked, if the ionising agent is wave radiation, it must be so penetrating as to be of Röntgen type; but he disbelieves in the emission by the sun of an adequate amount of such radiation (Elias, however, for a time considered such rays to be the cause of the E-layer).