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Parallel Electrostatic Waves Associated With Turbulent Plasma Mixing in the Kelvin‐Helmholtz Instability
Author(s) -
Wilder F. D.,
Schwartz S. J.,
Ergun R. E.,
Eriksson S.,
Ahmadi N.,
Chasapis A.,
Newman D. L.,
Burch J. L.,
Torbert R. B.,
Strangeway R. J.,
Giles B. L.
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 - 10.1029/2020gl087837
Subject(s) - physics , vortex , instability , turbulence , magnetosphere , geophysics , dissipation , mechanics , computational physics , plasma , classical mechanics , quantum mechanics
Abstract The Kelvin‐Helmholtz Instability (KHI) is thought to be an important driver of mass and momentum transfer from the solar wind to the Earth's magnetosphere. We present observations from NASA's Magnetospheric Multiscale mission of ion acoustic‐like waves associated with turbulence during the KHI interval on 8 September 2015. These parallel electrostatic waves are nonlinear, can have amplitudes in excess of 100 mV/m, and may be associated with a field‐aligned potential drop. We perform a survey of all vortices in the 8 September 2015 event, investigating the occurrence of electrostatic waves below the ion plasma frequency. We find that they tend to occur in the turbulent region in the middle of the KHI vortices, independent of the presence of compressed or intermittent currents. This suggests that the waves occur in the presence of plasma mixing in the vortex region and that they may play a part in the overall turbulent dissipation process.