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| Titel |
Modelling of N21P emission rates in aurora using various cross sections for excitation |
| VerfasserIn |
M. Ashrafi, B. S. Lanchester, D. Lummerzheim, N. Ivchenko, O. Jokiaho |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 27, no. 6 ; Nr. 27, no. 6 (2009-06-24), S.2545-2553 |
| Datensatznummer |
250016567
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| Publikation (Nr.) |
 copernicus.org/angeo-27-2545-2009.pdf |
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| Zusammenfassung |
| Measurements of N21P auroral emissions from the (4,1) and (5,2)
bands have been made at high temporal and spatial resolution in
the region of the magnetic zenith. The instrument used was the
auroral imager ASK, situated at Ramfjordmoen, Norway (69.6 N,
19.2 E) on 22 October 2006. Measurements from the European
Incoherent Scatter Radar (EISCAT) have been combined with the
optical measurements, and incorporated into an ionospheric model
to obtain height profiles of electron density and emission rates
of the N21P bands. The radar data provide essential
verification that the energy flux used in the model is correct.
One of the most important inputs to the model is the cross section
for excitation to the B3Πg electronic state, as well as
the cross sections to higher states from which cascading into the
B state occurs. The balance equations for production and loss of
the populations of all levels in each state are solved in order to
find the cascade contributions. Several sets of cross sections
have been considered, and selected cross sections have been used
to construct "emission" cross sections for the observed bands. The
resulting brightnesses are compared with those measured by ASK.
The importance of specific contributions from cascading is found,
with more than 50% of the total brightness resulting from
cascading. The cross sections used are found to produce a range of
brightnesses well within the uncertainty of both the modelled and
measured values. |
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