3D Space-Time Adaptive Hybrid Simulations of Magnetosheath High-Speed Jets

摘要

We study the generation and evolution of spatially localized dynamic plasma pressure enhancements in the magnetosheath (high-speed jets) by carrying out three-dimensional hybrid simulations of the Earth's dayside magnetosphere with a novel, space-time adaptive code, HYPERS. Highspeed jets are shown to occur downstream of quasi-parallel bow shocks under southward and northward quasi-radial interplanetary magnetic field conditions. The physical properties and three-dimensional morphology of simulation jets are found to be consistent with general statistical knowledge acquired from the satellite observations. We discuss a "magnetokinetic" mechanism for jet origin whereby the compression of solar wind plasma and its penetration into the magnetosheath is tied to the turbulencedriven magnetic field perturbations. We compare three-dimensional jets to dynamic pressure structures observed in two-dimensional hybrid simulations and demonstrate the impact of large jets on the magnetopause and the cusp.