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Variability of the Solar Wind Flow Asymmetry in the Martian Magnetosheath Observed by MAVEN
Author(s) -
Romanelli N.,
DiBraccio G.,
Halekas J.,
Dubinin E.,
Gruesbeck J.,
Espley J.,
Poh G.,
Ma Y.,
Luhmann J. G.
Publication year - 2020
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 - 10.1029/2020gl090793
Subject(s) - magnetosheath , martian , physics , solar wind , asymmetry , mars exploration program , atmosphere of mars , magnetopause , interplanetary magnetic field , geophysics , atmospheric sciences , interplanetary spaceflight , atmosphere (unit) , astrophysics , geology , magnetic field , astrobiology , meteorology , quantum mechanics
We perform the first statistical analysis of effects that different external conditions have on a solar wind (SW) flow asymmetry observed in the Martian magnetosheath due to mass loading, making use of ∼ 5 years of Mars Atmosphere and Volatile EvolutioN (MAVEN) observations. We find that the difference between the mean magnetosheath SW velocity component along the SW convective electric field direction in regions in the positive and negative hemispheres displays a strong linear correlation with the ratio between the upstream Interplanetary Magnetic Field (IMF) cross‐flow component ( B y ) and the SW proton density ( n s w ). The asymmetry is maximized ( ∼ 25–35 km s −1 ) for low n s w ( ∼ 1 cm −3 ) and large IMF B y ( ∼ 2 nT). These results suggest that the SW flow asymmetry variability is due to a force arising from the differential streaming between SW protons and oxygen ions, with boundary conditions partly defined by the pristine SW properties.