Structure and composition of the neutral upper atmosphere of Mars from the MAVEN NGIMS investigation.
The Mars Atmosphere and Volatile EvolutioN (MAVEN) Neutral Gas and Ion Mass Spectrometer (NGIMS) provides sensitive detections of neutral gas and ambient ion composition. NGIMS measurements of nine atomic and molecular neutral species, and their variation with altitude, latitude, and solar zenith angle are reported over several months of operation of the MAVEN mission. Sampling NGIMS signals from multiple neutral species every several seconds reveals persistent and unexpectedly large amplitude density structures. The scale height temperatures are mapped over the course of the first few months of the mission from high down to midlatitudes. NGIMS measurements near the homopause of40Ar/N2ratios agree with those reported by the Sample Analysis at Mars investigation and allow the altitude of the homopause for the most abundant gases to be established.
Planetary Environments Laboratory, Code 699 NASA Goddard Space Flight Center Greenbelt Maryland USA.
P R
PR
Mahaffy
Planetary Environments Laboratory, Code 699 NASA Goddard Space Flight Center Greenbelt Maryland USA; CRESST University of Maryland, Baltimore County Baltimore Maryland USA.
M
M
Benna
Planetary Environments Laboratory, Code 699 NASA Goddard Space Flight Center Greenbelt Maryland USA; CRESST University of Maryland College Park Maryland USA.
M
M
Elrod
University of Arizona Tucson Arizona USA.
R V
RV
Yelle
University of Michigan Ann Arbor Michigan USA.
S W
SW
Bougher
University of Arizona Tucson Arizona USA.
S W
SW
Stone
University of Colorado Boulder Boulder Colorado USA.
B M
BM
Jakosky
Mars; atmospheric structure; neutral composition; scale height; temperature; upper atmosphere
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