Auroral excitation of optical emissions of atomic and molecular oxygen
Abstract
Rocket measurements of the O I 'green line' (1S-1D) at 5577 A and the O2 (0, 0) atmospheric band at 7620 A were made in a steady IBC II+ aurora, simultaneously with measurements of N2 emissions and the auroral electron flux. An empirical model based on these data demonstrates that the principal excitation source of O2(b1Σg+) is energy transfer from O(1D), with direct electron impact of O2 contributing less than 5%. The altitude profile of the green line emission, taking into account quenching of O(1S) by O(3P) near the lower border of the aurora, resembles what would be produced by electron impact excitation of O2 but would require a dissociative excitation cross section of 10-6 cm2. None of the other known O(1S) excitation mechanisms are capable of producing the observed emission rate.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- June 1978
- DOI:
- 10.1029/JA083iA06p02511
- Bibcode:
- 1978JGR....83.2511F
- Keywords:
-
- Atomic Excitations;
- Auroral Electrojets;
- Light Emission;
- Molecular Excitation;
- Oxygen;
- Photometry;
- Energy Transfer;
- Mesosphere;
- Oxygen Atoms;
- Rocket Sounding;
- Stratosphere