Mars's Dayside Upper Ionospheric Composition Is Affected by Magnetic Field Conditions.

Autor: Withers P; Department of Astronomy, Boston University, Boston, MA, USA.; Center for Space Physics, Boston University, Boston, MA, USA., Flynn CL; Department of Astronomy, Boston University, Boston, MA, USA., Vogt MF; Center for Space Physics, Boston University, Boston, MA, USA., Mayyasi M; Center for Space Physics, Boston University, Boston, MA, USA., Mahaffy P; Planetary Environments Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA., Benna M; Planetary Environments Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA., Elrod M; Planetary Environments Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA., McFadden JP; Space Sciences Laboratory, University of California, Berkeley, CA, USA., Dunn P; Space Sciences Laboratory, University of California, Berkeley, CA, USA., Liu G; Space Sciences Laboratory, University of California, Berkeley, CA, USA., Andersson L; Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA., England S; Department of Aerospace and Ocean Engineering, Virginia Tech, Blacksburg, VA, USA.
Jazyk: angličtina
Zdroj: Journal of geophysical research. Space physics [J Geophys Res Space Phys] 2019 Apr; Vol. 124 (4), pp. 3100-3109. Date of Electronic Publication: 2019 Apr 12.
DOI: 10.1029/2018ja026266
Abstrakt: Previous observations have shown that electron density and temperature in the dayside ionosphere of Mars vary between strongly and weakly magnetized regions of the planet. Here we use data from the Neutral Gas and Ion Mass Spectrometer (NGIMS) on the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft to examine whether dayside ion densities and ionospheric composition also vary. We find that O + , O 2 + , and CO 2 + densities above ~200 km are greater in strongly magnetized regions than in weakly magnetized regions. Fractional abundances of ion species are also affected. The O + / O 2 + ratio at 300-km altitude increases from ~0.5 in strongly magnetized regions to ~0.8 in weakly magnetized regions. Consequently, the plasma reservoir available for escape is fundamentally different between strongly magnetized and weakly magnetized regions.
Databáze: MEDLINE
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