IGGCAS OpenIR  > 地球与行星物理院重点实验室
On the Hardness of the Photoelectron Energy Spectrum Near Mars
Wu, X. -S.1,2,3; Cui, J.1,2,3; Cao, Y. -T.1; Liu, L. - J.2,3; Zhou, Z. -J.2,3; Huang, Y. -Y.3; He, F.4; Wei, Y.4
2019-11-06
Source PublicationJOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
ISSN2169-9097
Pages9
AbstractPhotoelectrons are an important population of the dayside Martian upper atmosphere that contributes substantially to the local ionization and heat balances. This study is focused on the broad shape of the photoelectron energy spectrum at 10-50 eV. Assuming a power law distribution, we derive the hardness of each photoelectron energy spectrum measured on the dayside of Mars by the Solar Wind Electron Analyzer on board the Mars Atmosphere and Volatile Evolution spacecraft. Our analysis reveals two distinctive features: (1) The hardness tends to increase with decreasing altitude down to 140 km and then decrease toward lower altitudes; (2) the hardness tends to decrease with increasing solar zenith angle. These variations are restricted to regions below 250 km whereas the hardness appears to be fairly constant at higher altitudes. In practice, the hardness is modulated by the ionization of atmospheric neutrals by solar Extreme Ultraviolet and X-ray photons, inelastic collisions with atmospheric neutrals, Coulomb collisions with ionospheric thermal electrons, and photoelectron transport. While inelastic collisions tend to harden the photoelectron energy spectrum, both primary production and Coulomb collisions tend to soften it instead. We argue that the observed variations of the hardness can be understood in terms of the relative contributions of different processes. Our analysis also suggests the presence of appreciable temporal variability in hardness with a typical timescale of 10 min.
KeywordMars photoelectron
DOI10.1029/2019JE006093
Funding OrganizationStrategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China
WOS KeywordAE-E MEASUREMENTS ; ATMOSPHERE EXPLORER ; ELECTRON ; PREDICTIONS ; IONOSPHERE ; DEPOSITION ; FLUXES ; MODEL ; PEAKS
Language英语
Funding ProjectStrategic Priority Research Program of the Chinese Academy of Sciences[XDA17010201] ; National Science Foundation of China[41525015] ; National Science Foundation of China[41774186] ; National Science Foundation of China[41525016]
Funding OrganizationStrategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; National Science Foundation of China ; National Science Foundation of China
WOS Research AreaGeochemistry & Geophysics
WOS SubjectGeochemistry & Geophysics
WOS IDWOS:000494629800001
PublisherAMER GEOPHYSICAL UNION
Citation statistics
Document Type期刊论文
Identifierhttp://ir.iggcas.ac.cn/handle/132A11/95708
Collection地球与行星物理院重点实验室
Corresponding AuthorCui, J.
Affiliation1.Chinese Acad Sci, Natl Astron Observ, Beijing, Peoples R China
2.Sun Yat Sen Univ, Sch Atmospher Sci, Zhuhai, Peoples R China
3.Chinese Acad Sci, Ctr Excellence Comparat Planetol, Hefei, Anhui, Peoples R China
4.Chinese Acad Sci, Inst Geol & Geophys, Beijing, Peoples R China
Recommended Citation
GB/T 7714
Wu, X. -S.,Cui, J.,Cao, Y. -T.,et al. On the Hardness of the Photoelectron Energy Spectrum Near Mars[J]. JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS,2019:9.
APA Wu, X. -S..,Cui, J..,Cao, Y. -T..,Liu, L. - J..,Zhou, Z. -J..,...&Wei, Y..(2019).On the Hardness of the Photoelectron Energy Spectrum Near Mars.JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS,9.
MLA Wu, X. -S.,et al."On the Hardness of the Photoelectron Energy Spectrum Near Mars".JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS (2019):9.
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