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Measurements of the Vorticity in the Bursty Bulk Flows
Author(s) -
Zhang L.Q.,
Baumjohann W.,
Dai L.,
Khotyaintsev Yu V.,
Wang C.
Publication year - 2019
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 - 10.1029/2019gl084597
Subject(s) - physics , vorticity , vortex , potential vorticity , magnetic reconnection , turbulence , flux (metallurgy) , geophysics , zonal flow (plasma) , flow (mathematics) , kinetic energy , computational physics , ionosphere , eddy , mechanics , classical mechanics , magnetic field , plasma , materials science , quantum mechanics , metallurgy , tokamak
Abstract Curlometer analysis from 4‐point Magnetospheric Multiscale spacecraft measurements is applied to obtain the vorticity (ω) in the bursty bulk flow (BBF) from tail reconnection. Increases of the vorticity is associated with enhancements of the high‐energy ion flux (above 10 keV) and the flow speed during the BBF. Finger‐like structure, consisting of the lower‐energy ions below 10 keV, occurs mainly during intervals of small vorticity. The vorticity during BBF consistently shows a dominant − Z Geocentric solar magnetospheric (GSM) component, indicating clockwise vortexes in the flows. Combined with bipolar signals of Vy ‐geocentric solar magnetic, the Magnetospheric Multiscale observations provide evidence for flow eddies in the BBF. Power spectral analysis suggests existence of kinetic Alfvénic wave emissions, in addition to the flow eddy, in the high‐frequency regime in the BBF turbulence.