Observation of O<sup>+</sup> (<sup>4</sup>P-<sup>4</sup>D<sup>0</sup>) lines in electron aurora over Svalbard
This work reports on observations of O<sup>+</sup> lines in aurora over Svalbard, Norway. The Spectrographic Imaging Facility measures auroral spectra in three wavelength intervals (H<sub>β</sub>, N<sup>+</sup><sub>2</sub> 1N(0,2) and N<...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2004-09-01
|
| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/22/2805/2004/angeo-22-2805-2004.pdf |
| Summary: | This work reports on observations of O<sup>+</sup> lines in aurora over
Svalbard, Norway. The Spectrographic Imaging Facility measures auroral
spectra in three wavelength intervals
(H<sub>β</sub>, N<sup>+</sup><sub>2</sub> 1N(0,2) and N<sup>+</sup><sub>2</sub> 1N(1,3)).
The oxygen ion multiplet (4639-4696Å) is blended
with the band.
It is found that in electron aurora, the brightness
of this multiplet, is
on average, about 0.1 of the total brightness.
A joint optical and incoherent scatter radar study of an
electron aurora event shows that the ratio is enhanced
when the ionisation in the upper E-layer (140-190km)
is significant with respect to the E-layer peak
below 130km. Rayed arcs were observed on one such
occasion, whereas on other occasions the auroral
intensity was below the threshold of the imager.
A one-dimensional electron transport model is used to
estimate the cross section for production of the multiplet
in electron collisions, yielding 0.18x10<sup>-18</sup>cm<sup>2</sup>. |
|---|---|
| ISSN: | 0992-7689 1432-0576 |