Theory of formation of the ionosphere

Abstract

Current knowledge about the solar radiation and absorption and ionization cross sections of atmospheric gases is reviewed. Next the main observed features of ionospheric layers are summarized. Using CIRA 1965 model atmospheres the heights of the peak of the ionization rate are calculated for a number of solar emission lines and it is made clear which of these lines are responsible for the formation of E and FI layers. The mechanism of electron removal in the F and upper E regions as well as in the lower regions is considered, and the mechanism of formation and some behaviours of each ionospheric layer is discussed. In particular, the equatorial 1=2 layer is briefly considered. Discrepancies are pointed out between the values of the recombination coefficient and the rate constant for ion-atom interchange reaction obtained frmn ionospheric observations and from laboratory experiments. Inconsistency of the values of the intensity of solar radiation measured by rocket techniques and inferred from ionospheric considerations is also noted. Some evidence is presented suggesting that corpuscular radiation may be responsible for part of the ionization in the ionosphere even in temperate latitudes.

Low latitude ionosphere-thermosphere dynamics studies with inosonde chain in Southeast Asia

“…The principal mechanism of the ionospheric peak formation was first presented by Chapman (1931) for an idealized atmosphere, in which atmospheric density decays in an exponential way with altitude. The de-Correspondence to: T. Maruyama (tmaru@nict.go.jp) cay constant of the atmospheric species, or the scale height, determines hmF2 to attain equilibrium between chemical and diffusion processes (Yonezawa, 1966;Rishbeth et al, 1978). The actual ionosphere is not as simple as such a static picture suggests.…”

Using a neural network to make operational forecasts of ionospheric variations and storms at Kokubunji, Japan

“…The plasma density of ionosphere depends on the balance of production by photo-ionization and losses by a chemical recombination (Yonezawa, 1966). Thus, the ionosphere shows a variety of periodic fluctuations caused by the changes in the solar flux, season, and local time.…”

Topside ionospheric response to solar EUV variability

“…So even small differences in SZA can lead to large changes in the topside density. To first order, assuming the SZA dependence as predicted by the Chapman ionization theory [ Chapman , ; Yonezawa , ], the ionization should vary as the exponent of the secant of the SZA. In order to develop an improved metric of the behavior of the plasma around the peak of the F 2 layer and remove the effects of the SZA on ionization, Gulyaeva [] used ionosondes to derive a SZA correction factor to the ionospheric peak density.…”