 |
| Titel |
High resolution measurements and modeling of auroral hydrogen emission line profiles |
| VerfasserIn |
B. S. Lanchester, M. Galand, S. C. Robertson, M. H. Rees, D. Lummerzheim, I. Furniss, L. M. Peticolas, H. U. Frey, J. Baumgardner, M. Mendillo |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 21, no. 7 ; Nr. 21, no. 7, S.1629-1643 |
| Datensatznummer |
250014667
|
| Publikation (Nr.) |
 copernicus.org/angeo-21-1629-2003.pdf |
|
|
|
|
|
| Zusammenfassung |
Measurements in the
visible wavelength range at high spectral resolution (1.3 Å) have been made at
Longyearbyen, Svalbard (15.8 E,78.2 N) during an interval of intense proton
precipitation. The shape and Doppler shift of hydrogen Balmer beta line
profiles have been compared with model line profiles, using as input ion energy
spectra from almost coincident passes of the FAST and DMSP spacecraft. The
comparison shows that the simulation contains the important physical processes
that produce the profiles, and confirms that measured changes in the shape and
peak wave-length of the hydrogen profiles are the result of changing energy
input. This combination of high resolution measurements with modeling provides
a method of estimating the incoming energy and changes in flux of precipitating
protons over Svalbard, for given energy and pitch-angle distributions. Whereas
for electron precipitation, information on the incident particles is derived
from brightness and brightness ratios which require at least two spectral
windows, for proton precipitation the Doppler profile of resulting hydrogen
emission is directly related to the energy and energy flux of the incident
energetic protons and can be used to gather information about the source
region. As well as the expected Doppler shift to shorter wavelengths, the
measured profiles have a significant red-shifted component, the result of
upward flowing emitting hydrogen atoms.
Key words. Ionosphere (auroral
ionosphere; particle precipitation) – Magnetospheric physics (auroral
phenomena) |
| |
|
| Teil von |
|
|
|
|
|
|
|
|