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On the generation of Pi2 pulsations due to plasma flow patterns around magnetosheath jets
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  • Christos Katsavrias,
  • Savvas Raptis,
  • Ioannis A. Daglis,
  • Tomas Karlsson,
  • Marina Georgiou,
  • Georgios Balasis
Christos Katsavrias
University of Athens

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Savvas Raptis
Royal Institute of Technology
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Ioannis A. Daglis
National and Kapodistrian University of Athens
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Tomas Karlsson
KTH Royal Institute of Technology
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Marina Georgiou
National and Kapodistrian University of Athens
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Georgios Balasis
National Observatory of Athens
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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 seconds time-lag (which corresponds to the propagation time of a disturbance travelling with Alfvenic 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.
Aug 2021Published in Geophysical Research Letters volume 48 issue 15. 10.1029/2021GL093611