DOI: 10.1002/2015GL065084
论文题名: Electric Mars: The first direct measurement of an upper limit for the Martian polar wind electric potential
作者: Collinson G. ; Mitchell D. ; Glocer A. ; Grebowsky J. ; Peterson W.K. ; Connerney J. ; Andersson L. ; Espley J. ; Mazelle C. ; Sauvaud J.-A. ; Fedorov A. ; Ma Y. ; Bougher S. ; Lillis R. ; Ergun R. ; Jakosky B.
刊名: Geophysical Research Letters
ISSN: 0094-8511
EISSN: 1944-8242
出版年: 2015
卷: 42, 期: 21 起始页码: 9128
结束页码: 9134
语种: 英语
英文关键词: ambipolar
; atmospheric loss
; electric fields
; Mars
; polar wind
; unmagnetized planet
Scopus关键词: Drops
; Electric fields
; Electric potential
; Ionosphere
; NASA
; Photoelectron spectroscopy
; Upper atmosphere
; Ambipolar
; Direct measurement
; Escape velocities
; Ionospheric electron
; Mars
; Photoelectron spectrum
; Polar wind
; Volatile evolution
; Electric losses
; electric field
; electron
; gravity field
; instrumentation
; ionosphere
; magnetotail
; Martian atmosphere
; outflow
; plasma
; solar wind
英文摘要: An important mechanism in the generation of polar wind outflow is the ambipolar electric potential which assists ions in overcoming gravity and is a key mechanism for Terrestrial ionospheric escape. At Mars, open field lines are not confined to the poles, and outflow of ionospheric electrons is observed far into the tail. It has thus been hypothesized that a similar electric potential may be present at Mars, contributing to global ionospheric loss. However, no direct measurements of this potential have been made. In this pilot study, we examine photoelectron spectra measured by the Solar Wind Electron Analyzer instrument on the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) Mars Scout to put an initial upper bound on the total potential drop in the ionosphere of Mars of Φ♂â‰âs¥ 2V, with the possibility of a further â‰4.5 V potential drop above this in the magnetotail. If the total potential drop was close to the upper limit, then strong outflows of major ionospheric species (H+, O+, and O2+) would be expected. However, if most of the potential drop is confined below the spacecraft, as expected by current theory, then such a potential would not be sufficient on its own to accelerate O2+ to escape velocities, but would be sufficient for lighter ions. However, any potential would contribute to atmospheric loss through the enhancement of Jeans escape. © 2015. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84955200132&doi=10.1002%2f2015GL065084&partnerID=40&md5=7a233fed17e93ca67513255dd3fc01f4
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/8127
Appears in Collections: 科学计划与规划 气候变化与战略
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作者单位: NASA Goddard Spaceflight Center, Greenbelt, MD, United States
Recommended Citation:
Collinson G.,Mitchell D.,Glocer A.,et al. Electric Mars: The first direct measurement of an upper limit for the Martian polar wind electric potential[J]. Geophysical Research Letters,2015-01-01,42(21).