DOI: 10.1029/2018JE005560
Scopus记录号: 2-s2.0-85047469256
论文题名: Seasonal Variability of Neutral Escape from Mars as Derived From MAVEN Pickup Ion Observations
作者: Rahmati A. ; Larson D.E. ; Cravens T.E. ; Lillis R.J. ; Halekas J.S. ; McFadden J.P. ; Mitchell D.L. ; Thiemann E.M.B. ; Connerney J.E.P. ; Dunn P.A. ; Lee C.O. ; Eparvier F.G. ; DiBraccio G.A. ; Espley J.R. ; Luhmann J.G. ; Mazelle C. ; Jakosky B.M.
刊名: Journal of Geophysical Research: Planets
ISSN: 21699097
出版年: 2018
卷: 123, 期: 5 起始页码: 1192
结束页码: 1202
语种: 英语
英文关键词: Mars atmosphere
; MAVEN
; neutral escape
; particle detectors
; pickup ions
Scopus关键词: hydrogen
; ion
; Mars
; oxygen
; seasonal variation
英文摘要: The Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft arrived at Mars with the goal of determining the rates and mechanisms of atmospheric escape. Thermal hydrogen and hot oxygen escape are the two most important escape processes currently at work. Direct measurement of the escaping neutral hydrogen and oxygen atoms is impossible with current technology due to the low density and energy of escaping neutrals. However, when ionized and picked up by the solar wind, these escaping atoms can be detected by three particle detectors onboard MAVEN. By back-tracing the trajectories of measured pickup ions, constraints can be placed on the density of neutrals at altitudes not accessible by other measurement methods. In this work, pickup H+ and O+ data from the Solar Energetic Particle (SEP), Solar Wind Ion Analyzer (SWIA), and SupraThermal and Thermal Ion Composition (STATIC) instruments are used to assess the variability of neutral H and O exospheres at Mars. From an analysis of 2.5 Earth years of MAVEN data, we show that a strong H escape seasonal dependence is observed by SWIA and STATIC with inferred H escape rates as low as 3 × 1025 s−1 near aphelion and as high as 4 × 1026 s−1 near perihelion. Hot O escape rates derived from SEP, SWIA, and STATIC data imply a much less variable hot O exosphere with escape rates fluctuating by a factor of 2 around a mean value of 9 × 1025 s−1. Both escape rates are in general agreement with the most recent theoretical, modeled, and observationally inferred rates. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113923
Appears in Collections: 气候减缓与适应
There are no files associated with this item.
作者单位: Space Sciences Laboratory, University of California, Berkeley, CA, United States; Department of Physics and Astronomy, University of Kansas, Lawrence, KS, United States; Department of Physics and Astronomy, University of Iowa, Iowa City, IA, United States; Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, United States; NASA Goddard Space Flight Center, Greenbelt, MD, United States; IRAP/CNRS, Toulouse, France
Recommended Citation:
Rahmati A.,Larson D.E.,Cravens T.E.,et al. Seasonal Variability of Neutral Escape from Mars as Derived From MAVEN Pickup Ion Observations[J]. Journal of Geophysical Research: Planets,2018-01-01,123(5)