Analysis of 630.0-nm Emission Sources in Auroras

The role is considered of all known potential sources of excitation of the 1 D term of atomic oxygen in auroras and the value of their relative contributions to the emission intensity of 630.0-nm emission in the height interval of 100−300 km. The main attention is paid to the role of weak excitation sources of 1 D terms, such as collisional interactions between the components of atmospheric gases N( 2 D) + O, N( 2 D) + O 2 ,N( 2 P) + O 2 , and N + + O 2 ; direct electron impact O 2 + e*; and the radiative transition O( 1 S) → O( 1 D) + hν 557.7 . It is shown that, despite the small partial contributions of these sources to the intensity of the 630.0-nm emission, their total contribution can be quite significant. The total efficiency of these sources varies from 66 to 6% with an increase in altitude from 100 to 300 km and is significant at altitudes below 200 km. It is shown that the influence of the decontamination process leads to the fact that, in the region of heights of ∼110−150 km, the set of reactions of collisional interactions of ionospheric plasma components N( 2 D) + O, N( 2 D) + O 2 ,N( 2 P) + O 2 , and N + + O 2 becomes the second most efficient source contributing to the intensity of the 630.0-nm emission.