Direct observations of negative ions on the Lunar surface by Chang'E-6
Abstract The solar wind can interact directly with the surface of airless bodies like the Moon. The interaction causes sputtering of surface materials and solar wind ions are also partially backscattered to space. Particles leaving the surface can have any charge-state. At the Moon, backscattered or...
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Nature Portfolio
2025-06-01
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| Series: | Communications Earth & Environment |
| Online Access: | https://doi.org/10.1038/s43247-025-02399-7 |
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| author | Martin Wieser Aibing Zhang Romain Canu-Blot Wengjing Wang Gabriella Stenberg Wieser Lianghai Xie Stas Barabash Tianhua Zhong Xiao-Dong Wang Yongliao Zou Máté Kerényi Weibin Wen Charles Lue Chi Wang |
| author_facet | Martin Wieser Aibing Zhang Romain Canu-Blot Wengjing Wang Gabriella Stenberg Wieser Lianghai Xie Stas Barabash Tianhua Zhong Xiao-Dong Wang Yongliao Zou Máté Kerényi Weibin Wen Charles Lue Chi Wang |
| author_sort | Martin Wieser |
| collection | DOAJ |
| description | Abstract The solar wind can interact directly with the surface of airless bodies like the Moon. The interaction causes sputtering of surface materials and solar wind ions are also partially backscattered to space. Particles leaving the surface can have any charge-state. At the Moon, backscattered or sputtered positive ions1–4 and energetic neutral atoms5–8 have been observed, but all attempts to find negative ions in electron measurements have failed so far. Here we present measurements by Chang’E-6 from the lunar farside9 revealing the existence of a layer of negative ions close to the lunar surface. We found that about $$2.{5}_{-0.8}^{+1.2} \%$$ 2 . 5 − 0.8 + 1.2 % of the impinging solar wind protons charge exchange on the lunar regolith and are backscattered as negative hydrogen ions. The negative ion fraction is similar to the observed positive ion fraction1,3. We estimate a H− surface density of $$0.1{8}_{-0.03}^{+0.04}\,{{{{\rm{cm}}}}}^{-3}$$ 0.1 8 − 0.03 + 0.04 cm − 3 . On the dayside, the lifetime of negative hydrogen ions is short due to photodetachment10, confining them to a layer with a scale height of about 10 km. Such surface-bound layers or regions with negative ions should exist at any planetary object with a surface directly exposed to solar wind11,12, including low gravity bodies such as asteroids or comets. |
| format | Article |
| id | doaj-art-9879ad0822ff40dca2d982645e6f4e4d |
| institution | DOAJ |
| issn | 2662-4435 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Communications Earth & Environment |
| spelling | doaj-art-9879ad0822ff40dca2d982645e6f4e4d2025-08-20T03:21:06ZengNature PortfolioCommunications Earth & Environment2662-44352025-06-016111010.1038/s43247-025-02399-7Direct observations of negative ions on the Lunar surface by Chang'E-6Martin Wieser0Aibing Zhang1Romain Canu-Blot2Wengjing Wang3Gabriella Stenberg Wieser4Lianghai Xie5Stas Barabash6Tianhua Zhong7Xiao-Dong Wang8Yongliao Zou9Máté Kerényi10Weibin Wen11Charles Lue12Chi Wang13Swedish Institute of Space Physics (IRF)National Space Science Center (NSSC), Chinese Academy of Sciences (CAS)Swedish Institute of Space Physics (IRF)National Space Science Center (NSSC), Chinese Academy of Sciences (CAS)Swedish Institute of Space Physics (IRF)National Space Science Center (NSSC), Chinese Academy of Sciences (CAS)Swedish Institute of Space Physics (IRF)National Space Science Center (NSSC), Chinese Academy of Sciences (CAS)Swedish Institute of Space Physics (IRF)National Space Science Center (NSSC), Chinese Academy of Sciences (CAS)Swedish Institute of Space Physics (IRF)National Astronomical Observatories, Chinese Academy of SciencesSwedish Institute of Space Physics (IRF)National Space Science Center (NSSC), Chinese Academy of Sciences (CAS)Abstract The solar wind can interact directly with the surface of airless bodies like the Moon. The interaction causes sputtering of surface materials and solar wind ions are also partially backscattered to space. Particles leaving the surface can have any charge-state. At the Moon, backscattered or sputtered positive ions1–4 and energetic neutral atoms5–8 have been observed, but all attempts to find negative ions in electron measurements have failed so far. Here we present measurements by Chang’E-6 from the lunar farside9 revealing the existence of a layer of negative ions close to the lunar surface. We found that about $$2.{5}_{-0.8}^{+1.2} \%$$ 2 . 5 − 0.8 + 1.2 % of the impinging solar wind protons charge exchange on the lunar regolith and are backscattered as negative hydrogen ions. The negative ion fraction is similar to the observed positive ion fraction1,3. We estimate a H− surface density of $$0.1{8}_{-0.03}^{+0.04}\,{{{{\rm{cm}}}}}^{-3}$$ 0.1 8 − 0.03 + 0.04 cm − 3 . On the dayside, the lifetime of negative hydrogen ions is short due to photodetachment10, confining them to a layer with a scale height of about 10 km. Such surface-bound layers or regions with negative ions should exist at any planetary object with a surface directly exposed to solar wind11,12, including low gravity bodies such as asteroids or comets.https://doi.org/10.1038/s43247-025-02399-7 |
| spellingShingle | Martin Wieser Aibing Zhang Romain Canu-Blot Wengjing Wang Gabriella Stenberg Wieser Lianghai Xie Stas Barabash Tianhua Zhong Xiao-Dong Wang Yongliao Zou Máté Kerényi Weibin Wen Charles Lue Chi Wang Direct observations of negative ions on the Lunar surface by Chang'E-6 Communications Earth & Environment |
| title | Direct observations of negative ions on the Lunar surface by Chang'E-6 |
| title_full | Direct observations of negative ions on the Lunar surface by Chang'E-6 |
| title_fullStr | Direct observations of negative ions on the Lunar surface by Chang'E-6 |
| title_full_unstemmed | Direct observations of negative ions on the Lunar surface by Chang'E-6 |
| title_short | Direct observations of negative ions on the Lunar surface by Chang'E-6 |
| title_sort | direct observations of negative ions on the lunar surface by chang e 6 |
| url | https://doi.org/10.1038/s43247-025-02399-7 |
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