Electric and magnetic variations in the near-Mars environment

C. M Fowler; L Andersson; J Halekas; J. R Espley; C Mazelle; E. R Coughlin; R. E Ergun; David J Andrews; J. E. P Connerney; B Jakosky

doi:10.1002/2016JA023411

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Electric and magnetic variations in the near-Mars environment

Journal article

Peer reviewed

Electric and magnetic variations in the near-Mars environment

C. M Fowler, L Andersson, J Halekas, J. R Espley, C Mazelle, E. R Coughlin, R. E Ergun, David J Andrews, J. E. P Connerney and B Jakosky

Journal of Geophysical Research - Space Physics, Vol.122(8), pp.8536-8559

2017

DOI: 10.1002/2016JA023411

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Abstract

For the first time at Mars the statistical distribution of (1-D) electric field wave power in the magnetosphere is presented, along with the distribution of magnetic field wave power, as observed by the Mars Atmosphere and Volatile EvolutioN spacecraft from the first 14.5months of the mission. Wave power in several different frequency bands was investigated, and the strongest wave powers were observed at the lowest frequencies. The presented statistical studies suggest that the full thermalization of ions within the magnetosheath does not appear to occur, as has been predicted by previous studies. Manual inspection of 140 periapsis passes on the dayside shows that Poynting fluxes (at 2-16 Hz) between similar to 10(-11) and 10(-8) Wm(-2) reach the upper ionosphere for all 140 cases. Wave power is not observed in the ionosphere for integrated electron densities greater than 10(10.8)cm(-2), corresponding to typical depths of 100-200 km. The observations presented support previous suggestions that energy from the Mars-solar wind interaction can propagate into the upper ionosphere and may provide an ionospheric heating source. Upstream of the shock, the orientation of the solar wind interplanetary magnetic field was shown to significantly affect the statistical distribution of wave power, based on whether the spacecraft was likely magnetically connected to the shock or not-something that is predicted but has not been quantitatively shown at Mars before. In flight performance and caveats of the Langmuir Probe and Waves electric field power spectra are also discussed.

Natural Sciences

Physical Sciences

Astronomi, astrofysik och kosmologi

Astronomy, Astrophysics and Cosmology

electric

Fysik

magnetic

Mars

MAVEN

Naturvetenskap

power

wave

Details

Title: Subtitle: Electric and magnetic variations in the near-Mars environment
Creators: C. M Fowler - University of Colorado Boulder
L Andersson - University of Colorado Boulder
J Halekas - University of Iowa
J. R Espley - Goddard Space Flight Center
C Mazelle - Université de Toulouse
E. R Coughlin - University of California, Berkeley
R. E Ergun - University of Colorado Boulder
David J Andrews - Swedish Institute
J. E. P Connerney - Goddard Space Flight Center
B Jakosky - University of Colorado Boulder
Resource Type: Journal article
Publication Details: Journal of Geophysical Research - Space Physics, Vol.122(8), pp.8536-8559
DOI: 10.1002/2016JA023411
ISSN: 2169-9402
eISSN: 2169-9402
Grant note: DOI: 10.13039/100000104, name: National Aeronautics and Space Administration, award: PF6-170150
Language: English
Date published: 2017
Academic Unit: Physics and Astronomy
Record Identifier: 9984199767802771

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