AbstractWe 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. High‐speed 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 turbulence‐driven 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.