The mechanism of ionospheric ionization. II

The available mechanisms for the production of electrons in the three regions of the ionosphere are discussed with special reference to the question whether it is possible to account for the observed electron densities without supposing that the sun emits far more energy in the remote ultra-violet spectrum than would be emitted by a black body at 6000°. The contributions to electron densities made by metastable states of atoms and molecules are examined. It is concluded that the observed electron densities may be accounted for without requiring high solar energy in the ultra-violet if the effective recombination coefficient in theF 2 region is 10-11 . TheF 2 region is supposed formed by the ionization of atomic oxygen, and theE region by the ionization of molecular oxygen. The electrons forming theF 1 region are supposed to be provided by metastable N2 or by NO.