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<front>
<journal-meta>
<journal-id journal-id-type="publisher">EGUsphere</journal-id>
<journal-title-group>
<journal-title>EGUsphere</journal-title>
<abbrev-journal-title abbrev-type="publisher">EGUsphere</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">EGUsphere</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub"></issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/egusphere-2025-4119</article-id>
<title-group>
<article-title>The impact of electron precipitation on Earth&apos;s thermospheric NO production and the drag of LEO satellites</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Scherf</surname>
<given-names>Manuel</given-names>
<ext-link>https://orcid.org/0000-0002-8053-1041</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Krauss</surname>
<given-names>Sandro</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Tsurikov</surname>
<given-names>Grigory</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Strasser</surname>
<given-names>Andreas</given-names>
<ext-link>https://orcid.org/0009-0005-1162-5457</ext-link>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Shematovich</surname>
<given-names>Valery</given-names>
<ext-link>https://orcid.org/0000-0002-1062-1287</ext-link>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Bisikalo</surname>
<given-names>Dmitry</given-names>
<ext-link>https://orcid.org/0000-0003-2025-5564</ext-link>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Lammer</surname>
<given-names>Helmut</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Guedel</surname>
<given-names>Manuel</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Moestl</surname>
<given-names>Christian</given-names>
<ext-link>https://orcid.org/0000-0001-6868-4152</ext-link>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Space Research Institute, Austrian Academy of Sciences, Graz, Austria</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Institute of Geodesy, Technical University, Graz, Austria</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Institute of Astronomy, Russian Academy of Sciences, Moscow, Russian Federation</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>National Center of Physics and Mathematics, Sarov, Russian Federation</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Department of Astrophysics, University of Vienna, Vienna, Austria</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>Austrian Space Weather Office, GeoSphere Austria, Graz, Austria</addr-line>
</aff>
<pub-date pub-type="epub">
<day>29</day>
<month>08</month>
<year>2025</year>
</pub-date>
<volume>2025</volume>
<fpage>1</fpage>
<lpage>23</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2025 Manuel Scherf et al.</copyright-statement>
<copyright-year>2025</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4119/">This article is available from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4119/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4119/egusphere-2025-4119.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4119/egusphere-2025-4119.pdf</self-uri>
<abstract>
<p>We investigate the response of space weather events on Earth&apos;s upper atmosphere over the polar regions by studying their effect on the drag of the CHAMP and GRACE satellites. Increasing solar activity that results in heating and the expansion of the upper atmosphere threatens low Earth orbit (LEO) satellites. Auroral events are closely related to the stellar energy deposition of solar EUV radiation and precipitating energetic electrons, which influence photochemical processes such as the production of nitric oxide (NO) in the upper atmosphere. To study the production of NO molecules and their influence on the thermospheric structure and satellite drag, we first model Earth&amp;rsquo;s background thermosphere structure with the 1D upper atmosphere model Kompot by considering the incident X-ray, EUV, and IR radiation during selected space weather events. For investigating the effect of electron precipitation in the production of NO molecules in the polar thermosphere, we apply a Monte Carlo model that takes into account the stochastic nature of collisional scattering of auroral electrons in collisions with the surrounding N&lt;sub&gt;2&lt;/sub&gt;-O&lt;sub&gt;2&lt;/sub&gt; atmosphere, including the production of suprathermal N atoms. The observed effect of the atmospheric drag on the CHAMP and GRACE spacecraft during the two studied events indicates that a sporadic enhancement of NO molecule production in the polar thermosphere and its IR-cooling capability, which counteracts thermospheric expansion and can lead to an &quot;overcooling&quot; with decreased density after the space weather event, can have a protective effect on LEO satellites. Their production efficiency, however, is highly dependent on the energy flux of the precipitating electrons.</p>
</abstract>
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<funding-group>
<award-group id="gs1">
<funding-source>Austrian Science Fund</funding-source>
<award-id>33620-N</award-id>
<award-id>6857-N.</award-id>
</award-group>
<award-group id="gs2">
<funding-source>Russian Science Foundation</funding-source>
<award-id>22-12-00364-p</award-id>
</award-group>
<award-group id="gs3">
<funding-source>European Research Council</funding-source>
<award-id>HELIO4CAST, 10.3030/101042188)</award-id>
</award-group>
</funding-group>
</article-meta>
</front>
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