Structure, dynamics, and seasonal variability of the Mars‐solar wind interaction: MAVEN Solar Wind Ion Analyzer in‐flight performance and science results

J. S Halekas; S Ruhunusiri; Y Harada; G Collinson; D. L Mitchell; C Mazelle; J. P McFadden; J. E. P Connerney; J. R Espley; F Eparvier; J. G Luhmann; B. M Jakosky

doi:10.1002/2016JA023167

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Structure, dynamics, and seasonal variability of the Mars‐solar wind interaction: MAVEN Solar Wind Ion Analyzer in‐flight performance and science results

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Structure, dynamics, and seasonal variability of the Mars‐solar wind interaction: MAVEN Solar Wind Ion Analyzer in‐flight performance and science results

J. S Halekas, S Ruhunusiri, Y Harada, G Collinson, D. L Mitchell, C Mazelle, J. P McFadden, J. E. P Connerney, J. R Espley, F Eparvier, …

Journal of geophysical research. Space physics, Vol.122(1), pp.547-578

01/2017

DOI: 10.1002/2016JA023167

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Abstract

We report on the in‐flight performance of the Solar Wind Ion Analyzer (SWIA) and observations of the Mars‐solar wind interaction made during the Mars Atmosphere and Volatile EvolutioN (MAVEN) prime mission and a portion of its extended mission, covering 0.85 Martian years. We describe the data products returned by SWIA and discuss the proper handling of measurements made with different mechanical attenuator states and telemetry modes, and the effects of penetrating and scattered backgrounds, limited phase space coverage, and multi‐ion populations on SWIA observations. SWIA directly measures solar wind protons and alpha particles upstream from Mars. SWIA also provides proxy measurements of solar wind and neutral densities based on products of charge exchange between the solar wind and the hydrogen corona. Together, upstream and proxy observations provide a complete record of the solar wind experienced by Mars, enabling organization of the structure, dynamics, and ion escape from the magnetosphere. We observe an interaction that varies with season and solar wind conditions. Solar wind dynamic pressure, Mach number, and extreme ultraviolet flux all affect the bow shock location. We confirm the occurrence of order‐of‐magnitude seasonal variations of the hydrogen corona. We find that solar wind Alfvén waves, which provide an additional energy input to Mars, vary over the mission. At most times, only weak mass loading occurs upstream from the bow shock. However, during periods with near‐radial interplanetary magnetic fields, structures consistent with Short Large Amplitude Magnetic Structures and their wakes form upstream, dramatically reconfiguring the Martian bow shock and magnetosphere. Key Points SWIA provides direct and proxy measurements of solar wind input to Mars The Mars‐solar wind interaction varies with solar wind conditions and season Mars only perturbs the upstream medium weakly, except during radial IMF

Mars

solar wind

Details

Title: Subtitle: Structure, dynamics, and seasonal variability of the Mars‐solar wind interaction: MAVEN Solar Wind Ion Analyzer in‐flight performance and science results
Creators: J. S Halekas - University of Iowa
S Ruhunusiri - University of Iowa
Y Harada - University of California, Berkeley
G Collinson - Goddard Space Flight Center
D. L Mitchell - University of California, Berkeley
C Mazelle - L'Institut de Recherche en Astrophysique et Planétologie Toulouse France
J. P McFadden - University of California, Berkeley
J. E. P Connerney - Goddard Space Flight Center
J. R Espley - Goddard Space Flight Center
F Eparvier - University of Colorado Boulder
J. G Luhmann - University of California, Berkeley
B. M Jakosky - University of Colorado Boulder
Resource Type: Journal article
Publication Details: Journal of geophysical research. Space physics, Vol.122(1), pp.547-578
DOI: 10.1002/2016JA023167
ISSN: 2169-9380
eISSN: 2169-9402
Number of pages: 32
Language: English
Date published: 01/2017
Academic Unit: Physics and Astronomy
Record Identifier: 9984199760402771

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