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On the Generation of Pi2 Pulsations due to Plasma Flow Patterns Around Magnetosheath Jets
Author(s) -
Katsavrias C.,
Raptis S.,
Daglis I. A.,
Karlsson T.,
Georgiou M.,
Balasis G.
Publication year - 2021
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 - 10.1029/2021gl093611
Subject(s) - magnetosheath , magnetopause , magnetosphere , physics , plasma , jet (fluid) , geophysics , magnetic field , magnetometer , astrophysics , computational physics , mechanics , quantum mechanics
We report observations of a magnetosheath jet followed by a period of decelerated background plasma. During this period, THEMIS‐A magnetometer showed abrupt disturbances which, in the wavelet spectrum, appeared as prominent and irregular pulsations in two frequency bands (7.6–9.2 and 12–17 mHz) within the Pi2 range. The observations suggest—for the first time to our knowledge—that these pulsations were locally generated by the abrupt magnetic field changes driven by the jet’s interaction with the ambient magnetosheath plasma. Furthermore, similar pulsations, detected by THEMIS‐D inside the magnetosphere with a 140 s time‐lag (which corresponds to the propagation time of a disturbance traveling with Alfvénic speed), are shown to be directly associated with the ones in the magnetosheath, which raises the question of how exactly these pulsations are propagated through the magnetopause.