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MAVEN observations of partially developed Kelvin‐Helmholtz vortices at Mars
Author(s) -
Ruhunusiri Suranga,
Halekas J. S.,
McFadden J. P.,
Connerney J. E. P.,
Espley J. R.,
Harada Y.,
Livi R.,
Seki K.,
Mazelle C.,
Brain D.,
Hara T.,
DiBraccio G. A.,
Larson D. E.,
Mitchell D. L.,
Jakosky B. M.,
Hasegawa H.
Publication year - 2016
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 - 10.1002/2016gl068926
Subject(s) - vortex , physics , magnetosheath , mars exploration program , ionosphere , ion , geophysics , magnetopause , mechanics , astrobiology , magnetosphere , plasma , quantum mechanics
Abstract We present preliminary results and interpretations for Mars Atmospheric and Volatile EvolutioN (MAVEN) observations of magnetosheath‐ionospheric boundary oscillations at Mars. Using centrifugal force arguments, we first predict that a signature of fully rolled up Kelvin‐Helmholtz vortices at Mars is sheath ions that have a bulk motion toward the Sun. The sheath ions adjacent to a vortex should also accelerate to speeds higher than the mean sheath velocity. We also predict that while the ionospheric ions that are in the vortex accelerate antisunward, they never attain speeds exceeding that of the sheath ions, in stark contrast to KH vortices that arise at the Earth's magnetopause. We observe accelerated sheath and ionospheric ions, but we do not observe sheath ions that have a bulk motion toward the Sun. Thus, we interpret these observations as KH vortices that have not fully rolled up.