Evidence for transient, local ion foreshocks caused by dayside magnetopause reconnection

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Pfau-Kempf , Y , Hietala , H , Milan , S E , Juusola , L , Hoilijoki , S , Ganse , U , von Alfthan , S & Palmroth , M 2016 , ' Evidence for transient, local ion foreshocks caused by dayside magnetopause reconnection ' , Annales Geophysicae , vol. 34 , no. 11 , pp. 943-959 . https://doi.org/10.5194/angeo-34-943-2016

Title: Evidence for transient, local ion foreshocks caused by dayside magnetopause reconnection
Author: Pfau-Kempf, Yann; Hietala, Heli; Milan, Steve E.; Juusola, Liisa; Hoilijoki, Sanni; Ganse, Urs; von Alfthan, Sebastian; Palmroth, Minna
Contributor organization: Department of Physics
Space Physics Research Group
Date: 2016-11-04
Language: eng
Number of pages: 17
Belongs to series: Annales Geophysicae
ISSN: 0992-7689
DOI: https://doi.org/10.5194/angeo-34-943-2016
URI: http://hdl.handle.net/10138/170133
Abstract: We present a scenario resulting in time-dependent behaviour of the bow shock and transient, local ion reflection under unchanging solar wind conditions. Dayside magnetopause reconnection produces flux transfer events driving fast-mode wave fronts in the magnetosheath. These fronts push out the bow shock surface due to their increased downstream pressure. The resulting bow shock deformations lead to a configuration favourable to localized ion reflection and thus the formation of transient, travelling foreshock-like field-aligned ion beams. This is identified in two-dimensional global magnetospheric hybrid-Vlasov simulations of the Earth's magnetosphere performed using the Vlasiator model (http://vlasiator.fmi.fi). We also present observational data showing the occurrence of dayside reconnection and flux transfer events at the same time as Geotail observations of transient foreshock-like field-aligned ion beams. The spacecraft is located well upstream of the fore-shock edge and the bow shock, during a steady southward interplanetary magnetic field and in the absence of any solar wind or interplanetary magnetic field perturbations. This indicates the formation of such localized ion foreshocks.
Subject: Interplanetary physics (planetary bow shocks)
magnetospheric physics (magnetosheath; solar wind-magnetosphere interactions)
FLUX-TRANSFER EVENTS
EARTHS BOW SHOCK
INTERPLANETARY MAGNETIC-FIELD
HIGH-LATITUDE MAGNETOPAUSE
ELEMENTARY CURRENT SYSTEMS
HYBRID-VLASOV SIMULATION
WIND SPACECRAFT
THEMIS OBSERVATIONS
CLUSTER SPACECRAFT
RADAR OBSERVATIONS
115 Astronomy, Space science
Peer reviewed: Yes
Rights: cc_by
Usage restriction: openAccess
Self-archived version: publishedVersion


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