Many transient physical processes operate simultaneously and couple nonlinearly in the near-Earth environment across turbulent spatio-temporal scales, producing strong impacts on the cusp, magnetopause and ionosphere that are difficult to fully understand and predict without kinetic simulations. In particular, under quasi-radial interplanetary magnetic field (IMF) conditions the turbulent magnetosheath flow generates large-amplitude, spatially localized dynamic pressure enhancements, known as magnetosheath jets or high-speed jets (Plaschke et al., 2018). These structures, commonly observed by satellites downstream of quasi-parallel bow shocks, carry significant amounts of momentum, energy and magnetic flux. Therefore, their generation mechanism, characteristic lifetimes, physical and geometric properties, and possible impact on the magnetosphere present strong interest to the space physics community.Based on observations in the past two decades, a great amount of statistical knowledge, as well as possible theoretical explanations relating the occurrence of jets to solar wind and foreshock conditions, have been accumulated (Plaschke et al., 2018(Plaschke et al., , 2020. In particular, a theory by Hietala et al. (2012Hietala et al. ( , 2009 suggests that plasma ripples, which inherently develop in the bow shock under quasi-radial IMF and high Mach solar wind conditions, may be responsible for producing local high-speed flows in the magnetosheath by deflecting the incoming solar wind plasma flow in the anti-sunward direction due to the local curvature of a shock front so that the speed of the deflected flow remains close to the upstream solar wind value.

The impact of high-speed jets—dynamic pressure enhancements in the magnetosheath—on the Earth's magnetopause has been observed to trigger local magnetic reconnection. We perform a three-dimensional hybrid simulation to study the magnetosheath and magnetopause under turbulent conditions using a quasi-radial southward interplanetary magnetic field (IMF). In contrast to quasi-steady reconnection with a strong southward IMF, we show that after the impact of a jet on the magnetopause, the magnetopause moves inward, the current sheet is compressed and intensified and signatures of local magnetic reconnection are observed, showing similarities to spacecraft measurements.

Using the combined Auburn global hybrid simulation code in 3-D (ANGIE3D) and the Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model, we investigate the self-consistent connection of fast flow injections from the tail plasma sheet and the inner magnetosphere under a southward IMF. In the dynamic run, the hybrid results provide the CIMI model with 3-D magnetic field and the electric potential at the high latitude ionosphere boundary as well as the full ion phase space distribution function at the CIMI outer boundary at the equator. The simulation shows that magnetotail reconnection, which has a dawn-dusk size of ∼1-5 R E , recurs with a period of several minutes, resulting in recurring localized fast flow injections. Strong ion temperature anisotropy and non-Maxwellian distributions are present in the fast flows, and the braking of fast flows due to the dipole-like field results in further perpendicular heating in the injection sources. Multiple fast flow injections lead to multiple peaks in the particle fluxes in the inner magnetosphere as well as layers of upward and downward fieldaligned currents at the ionosphere, and low energy particles penetrate deeper radially than the high energy particles. The combined ANGIE3D-CIMI model can be used to calculate the global kinetic physics that contains both Region-1 and Region-2 field-aligned currents. LIN ET AL.

The impact of high-speed jets -dynamic pressure enhancements in the magnetosheath -on the Earth's magnetopause has been observed to trigger local magnetic reconnection. We perform a three-dimensional hybrid simulation to study the magnetosheath and magnetopause under turbulent conditions using a quasi-radial southward interplanetary magnetic field (IMF). In contrast to quasi-steady reconnection with a strong southward IMF, we show that after the impact of a jet on the magnetopause, the magnetopause moves inwards, the current sheet is compressed and intensified and signatures of local magnetic reconnection are observed, showing similarities to spacecraft measurements.