Pfau-Kempf, Yann Hietala, Heli Milan, Steve E. Juusola, Liisa Hoilijoki, Sanni Ganse, Urs von Alfthan, Sebastian Palmroth, Minna Evidence for transient, local ion foreshocks caused by dayside magnetopause reconnection 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 foreshock 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. Science & Technology;Physical Sciences;Astronomy & Astrophysics;Geosciences, Multidisciplinary;Meteorology & Atmospheric Sciences;Geology;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 2017-03-09
    https://figshare.le.ac.uk/articles/journal_contribution/Evidence_for_transient_local_ion_foreshocks_caused_by_dayside_magnetopause_reconnection/10229192