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Field‐Aligned Potentials at Mars From MAVEN Observations
Author(s) -
Xu Shaosui,
Mitchell David L.,
McFadden James P.,
Collinson Glyn,
Harada Yuki,
Lillis Robert,
Mazelle Christian,
Connerney J. E. P.
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl080136
Subject(s) - ambipolar diffusion , mars exploration program , electric field , physics , atmospheric escape , solar wind , outflow , ion , ionosphere , computational physics , polar wind , atmosphere of mars , magnetic field , atomic physics , geophysics , electron , interplanetary magnetic field , astrobiology , martian , meteorology , quantum mechanics
One possible ion escape channel at Mars is a polar wind‐like outflow driven by parallel electric fields and/or other acceleration mechanisms. With independent potential estimates from ionospheric photoelectron measurements by the Solar Wind Electron Analyzer (SWEA) and ion measurements by the SupraThermal And Thermal Ion Composition (STATIC) onboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, magnetic field‐aligned potentials are calculated as the difference of the two. The calculated field‐aligned potentials have average values that range from 0 to −1.5 V, relative to the ionospheric source region. These field‐aligned potentials likely result from ambipolar electric fields and are found on both closed and open field lines. On the dayside, these potentials range from 0 to −0.7 V, corresponding to an electric field magnitude <3 mV/km, which peaks near the ion exobase and can effectively accelerate ions and enhance ion outflow.