University of Oulu

A.L. Mishev, P.I.Y. Velinov, Ionization effect in the Earth’s atmosphere during the sequence of October–November 2003 Halloween GLE events, Journal of Atmospheric and Solar-Terrestrial Physics, Volume 211, 2020, 105484, ISSN 1364-6826,

Ionization effect in the Earth’s atmosphere during the sequence of October–November 2003 Halloween GLE events

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Author: Mishev, A.L.1,2; Velinov, P.I.Y.3
Organizations: 1Space Physics and Astronomy Research Unit, University of Oulu, Finland
2Sodankylä Geophysical Observatory, University of Oulu, Finland
3Institute for Space Research and Technology, Bulgarian Academy of Sciences, Sofia, Bulgaria
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 5 MB)
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Language: English
Published: Elsevier, 2020
Publish Date: 2022-10-27


The effect of precipitating high-energy particles on atmospheric physics and chemistry is extensively studied over the last decade. In majority of the existing models, the precipitating particles induced ionization plays an essential role. For such effects, it is necessary to possess enhanced increase in ion production, specifically during the winter period. In this study, we focus on highly penetrating particles — cosmic rays. The galactic cosmic rays are the main source of ionization in the Earth’s stratosphere and troposphere. On the other hand, the atmospheric ionization may be significantly enhanced during strong solar energetic particle events, mainly over the polar caps. A specific interest is paid to the most energetic solar proton events leading to counting rate enhancement of ground-based detectors, namely the so-called ground level enhancements (GLEs). During solar cycle 23, several strong ground level enhancements were observed. A sequence of three GLEs was observed in October–November 2003, the Halloween events. Here, on the basis of 3-D Monte Carlo model, we computed the energetic particles induced atmospheric ionization, explicitly considering the contribution of cosmic rays with galactic and solar origin. The ion production rates were computed as a function of the altitude above sea level using reconstructed solar energetic particles spectra. The 24 h and event averaged ionization effects relative to the average due to galactic cosmic rays were also computed.

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Series: Journal of atmospheric and solar-terrestrial physics
ISSN: 1364-6826
ISSN-E: 1879-1824
ISSN-L: 1364-6826
Volume: 211
Article number: 105484
DOI: 10.1016/j.jastp.2020.105484
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: This work was supported by the Academy of Finland (project 330063 QUASARE, 321882 ESPERA and 304435 CRIPA-X).
Academy of Finland Grant Number: 321882
Detailed Information: 321882 (Academy of Finland Funding decision)
304435 (Academy of Finland Funding decision)
Dataset Reference: The NM records used in this study were retrieved from International GLE database and neutron monitor database
Copyright information: © 2020 Elsevier Ltd. This manuscript version is made available under the CC-BY-NC-ND 4.0 license