University of Oulu

Xu, W., Marshall, R. A., Fang, X., Turunen, E., & Kero, A. (2018). On the effects of bremsstrahlung radiation during energetic electron precipitation. Geophysical Research Letters, 45, 1167– 1176.

On the effects of bremsstrahlung radiation during energetic electron precipitation

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Author: Xu, Wei1; Marshall, Robert A.1; Fang, Xiaohua2;
Organizations: 1Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, USA
2Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA
3Sodankylä Geophysical Observatory, University of Oulu, Oulu, Finland
4Institute of Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
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Language: English
Published: American Geophysical Union, 2018
Publish Date: 2019-09-25


Precipitation of energetic particles into the Earth’s atmosphere can significantly change the properties, dynamics, as well as the chemical composition of the upper and middle atmosphere. In this paper, using Monte Carlo models, we simulate, from first principles, the interaction of monoenergetic beams of precipitating electrons with the atmosphere, with particular emphasis on the process of bremsstrahlung radiation and its resultant ionization production and atmospheric effects. The pitch angle dependence of the ionization rate profile has been quantified: the altitude of peak ionization rate depends on the pitch angle by a few kilometers. We also demonstrate that the transport of precipitating electron energy in the form of bremsstrahlung photons leads to ionization at altitudes significantly lower than the direct impact ionization, as low as ∼20 km for 1 MeV precipitating electrons. Moreover, chemical modeling results suggest that the chemical effects in the atmosphere due to bremsstrahlung‐induced ionization production during energetic electron precipitation are likely insignificant.

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Series: Geophysical research letters
ISSN: 0094-8276
ISSN-E: 1944-8007
ISSN-L: 0094-8276
Volume: 45
Issue: 2
Pages: 1167 - 1176
DOI: 10.1002/2017GL076510
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: This research was supported by the National Science Foundation grants AGS‐1243176 and AGS‐1732359. A.K. was supported by European Regional Development Fund (Regional Council of Lapland, decision number A70179).
Dataset Reference: The simulation data and analysis codes used to generate all figures and results in this paper are available at
Copyright information: © 2018. American Geophysical Union. All Rights Reserved.