Auroral emission from O₂(¹Δ_g)

Abstract

We describe a large enhancement of the O2(¹Δg ‐ ³Σg), infrared oxygen band at 1.27 µ in <IBC II auroras. A comparison with N2+ band intensity suggests that the O2 emission is too strong to be sustained by the electron flux responsible for N2+. Alternative sources of energy, such as chemical reactions and electric fields, are considered.

Preliminary results from the 1.27-micron measurements in the Boulder Ionospheric Modification Experiment

“…On the basis of current knowledge of processes by which O•(•Ag) (which yields radiation at 1.27 /•) can be excited, it was not expected that observable amounts of radiation would be produced. However, observations of 1.27-• radiation under auroral conditions [Noxon, 1970;Megill et al, 1970] also present an anomaly; the observed intensities are considerably larger than can be easily explained. On the basis of the auroral observations and on the premise that the excitation during auroras is due to 'heated' ambient electrons, observations of 1.27-/x radiation were perfo.rmed during the operation of the transmitter.…”

Observations of thermospheric dynamics at high latitudes from ground and space

“…(•Ag) with and without the inclusion of meridional transport and were able to show that the long lifetime of this state of molecular oxygen would indeed pump up the concentration of this metastable specie depending on the duration of the particle precipitation event and upon how quickly this specie was transported away by the wind. The detection of high emission rates from this species reported by Noxon [1970Noxon [ , 1982 had been a long-standing problem not adequately explained until the significance of meridional transport had become more apparent.…”

The study of intermolecular energy transfers in electronic energy quenching for molecular collisions N&lt;sub&gt;2&lt;/sub&gt;-N&lt;sub&gt;2&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;-O&lt;sub&gt;2&lt;/sub&gt;, O&lt;sub&gt;2&lt;/sub&gt;-O&lt;sub&gt;2&lt;/sub&gt;

“…Six vibrational levels of the b 1 + g state are effectively excited in the aurora with the subsequent emission of atmospheric bands (Vallance Jones and Gattinger, 1974;Henriksen and Sivjee, 1990;Witt, 2006). There is also a large enhancement of intensities of the infrared atmospheric band 1.27 µm in the aurora (Noxon, 1970;Gattinger and Vallance Jones, 1973;Baker et al, 1978). The mechanisms of the production of the singlet oxygen in the mesosphere and lower thermosphere and the emission in the infrared atmospheric and atmospheric band nightglow have been studied during a few decades (Llewellyn and Solheim, 1978;Witt et al, 1979;McDade et al, 1986McDade et al, , 1987Kita et al, 1992;Slanger et al, 2000.…”