Inversion of Upstream Solar Wind Parameters from ENA Observations at Mars
An algorithm has been developed to invert the solar wind parameters from the hydrogen energetic neutral atom (H-ENA) measured in near-Mars space. Supposing the H-ENA is produced by change exchange collision between protons that originated in the solar wind and neutrals in the exosphere, an H-ENA mod...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-03-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/15/7/1721 |
| _version_ | 1797607129265209344 |
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| author | Yiteng Zhang Lei Li Lianghai Xie Linggao Kong Wenya Li Binbin Tang Jijie Ma Aibing Zhang |
| author_facet | Yiteng Zhang Lei Li Lianghai Xie Linggao Kong Wenya Li Binbin Tang Jijie Ma Aibing Zhang |
| author_sort | Yiteng Zhang |
| collection | DOAJ |
| description | An algorithm has been developed to invert the solar wind parameters from the hydrogen energetic neutral atom (H-ENA) measured in near-Mars space. Supposing the H-ENA is produced by change exchange collision between protons that originated in the solar wind and neutrals in the exosphere, an H-ENA model is established based on the magnetohydrodynamic (MHD) simulation of the solar wind interaction with Mars, to study the H-ENA characteristics. It is revealed that the solar wind H-ENAs are high-speed, low-temperature beams, just like the solar wind, while the magnetosheath H-ENAs are slower and hotter, with broader energy distribution. Assuming Maxwellian velocity distribution, the solar wind H-ENA flux is best fitted by a Gaussian function, from which the solar wind velocity, density, and temperature can be retrieved. Further investigation, based on the ENA flux simulated by the H-ENA model, reveals that the accuracy of inversed solar wind parameters is related to the angular and energy resolutions of the ENA detector. Finally, the algorithm is verified using the H-ENA observations from the Tianwen-1 mission. The upstream solar wind velocity when inversed is close to that of the in situ plasma measurement. Our result suggests the solar wind parameters inversed from H-ENA observation could be an important supplement to the dataset supporting studies on the Martian space environment, where long-term continuous monitoring of the upstream SW condition is lacking. |
| first_indexed | 2024-03-11T05:26:51Z |
| format | Article |
| id | doaj.art-80faa9fcc8cc498080cb90f6c9022207 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-11T05:26:51Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-80faa9fcc8cc498080cb90f6c90222072023-11-17T17:27:57ZengMDPI AGRemote Sensing2072-42922023-03-01157172110.3390/rs15071721Inversion of Upstream Solar Wind Parameters from ENA Observations at MarsYiteng Zhang0Lei Li1Lianghai Xie2Linggao Kong3Wenya Li4Binbin Tang5Jijie Ma6Aibing Zhang7State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaNational Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaUniversity of Chinese Academy of Sciences, Beijing 100049, ChinaUniversity of Chinese Academy of Sciences, Beijing 100049, ChinaAn algorithm has been developed to invert the solar wind parameters from the hydrogen energetic neutral atom (H-ENA) measured in near-Mars space. Supposing the H-ENA is produced by change exchange collision between protons that originated in the solar wind and neutrals in the exosphere, an H-ENA model is established based on the magnetohydrodynamic (MHD) simulation of the solar wind interaction with Mars, to study the H-ENA characteristics. It is revealed that the solar wind H-ENAs are high-speed, low-temperature beams, just like the solar wind, while the magnetosheath H-ENAs are slower and hotter, with broader energy distribution. Assuming Maxwellian velocity distribution, the solar wind H-ENA flux is best fitted by a Gaussian function, from which the solar wind velocity, density, and temperature can be retrieved. Further investigation, based on the ENA flux simulated by the H-ENA model, reveals that the accuracy of inversed solar wind parameters is related to the angular and energy resolutions of the ENA detector. Finally, the algorithm is verified using the H-ENA observations from the Tianwen-1 mission. The upstream solar wind velocity when inversed is close to that of the in situ plasma measurement. Our result suggests the solar wind parameters inversed from H-ENA observation could be an important supplement to the dataset supporting studies on the Martian space environment, where long-term continuous monitoring of the upstream SW condition is lacking.https://www.mdpi.com/2072-4292/15/7/1721H-ENAMarssolar wind inversionTianwen-1MINPA |
| spellingShingle | Yiteng Zhang Lei Li Lianghai Xie Linggao Kong Wenya Li Binbin Tang Jijie Ma Aibing Zhang Inversion of Upstream Solar Wind Parameters from ENA Observations at Mars Remote Sensing H-ENA Mars solar wind inversion Tianwen-1 MINPA |
| title | Inversion of Upstream Solar Wind Parameters from ENA Observations at Mars |
| title_full | Inversion of Upstream Solar Wind Parameters from ENA Observations at Mars |
| title_fullStr | Inversion of Upstream Solar Wind Parameters from ENA Observations at Mars |
| title_full_unstemmed | Inversion of Upstream Solar Wind Parameters from ENA Observations at Mars |
| title_short | Inversion of Upstream Solar Wind Parameters from ENA Observations at Mars |
| title_sort | inversion of upstream solar wind parameters from ena observations at mars |
| topic | H-ENA Mars solar wind inversion Tianwen-1 MINPA |
| url | https://www.mdpi.com/2072-4292/15/7/1721 |
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