Lanchester, BS;
Galand, M;
Robertson, SC;
Rees, MH;
Lummerzheim, D;
Furniss, I;
Peticolas, LM;
... Mendillo, M; + view all
(2003)
High resolution measurements and modeling of auroral hydrogen emission line profiles.
Annales Geophysicae
, 21
(7)
1629 - 1643.
10.5194/angeo-21-1629-2003.
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Abstract
Measurements in the visible wavelength range at high spectral resolution (1.3 Angstrom) 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 wavelength 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.
| Type: | Article |
|---|---|
| Title: | High resolution measurements and modeling of auroral hydrogen emission line profiles |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.5194/angeo-21-1629-2003 |
| Publisher version: | http://dx.doi.org/10.5194/angeo-21-1629-2003 |
| Language: | English |
| Additional information: | This article was originally published in Annales Geophysicae. It may be re-used under the terms of the Creative Commons Attribution 3.0 License but not submitted for peer-reviewed publication elsewhere. |
| Keywords: | Ionosphere, Auroral ionosphere, Particle precipitation, Magnetospheric physics, Auroral phenomena, H-beta emission, Transport-theoretic model, Proton aurora, Photometric observations, Doppler profiles, Balmer alpha, Monte-carlo, Atom aurora, Atmosphere, Electron |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/9536 |
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