Abstract. We use a global hybrid-Vlasov simulation for the magnetosphere, Vlasiator, to
investigate magnetosheath high-speed jets. Unlike many other hybrid-kinetic
simulations, Vlasiator includes an unscaled geomagnetic dipole, indicating
that the simulation spatial and temporal dimensions can be given in SI units
without scaling. Thus, for the first time, this allows investigating the
magnetosheath jet properties and comparing them directly with the observed
jets within the Earth's magnetosheath. In the run shown in this paper, the
interplanetary magnetic field (IMF) cone angle is 30∘, and a
foreshock develops upstream of the quasi-parallel magnetosheath. We visually
detect a structure with high dynamic pressure propagating from the bow shock
through the magnetosheath. The structure is confirmed as a jet using three
different criteria, which have been adopted in previous observational
studies. We compare these criteria against the simulation results. We find
that the magnetosheath jet is an elongated structure extending earthward from
the bow shock by ∼2.6 RE, while its size perpendicular to
the direction of propagation is ∼0.5 RE. We also
investigate the jet evolution and find that the jet originates due to the
interaction of the bow shock with a high-dynamic-pressure structure that
reproduces observational features associated with a short, large-amplitude
magnetic structure (SLAMS). The simulation shows that magnetosheath jets can
develop also under steady IMF, as inferred by observational studies. To our
knowledge, this paper therefore shows the first global kinetic simulation of
a magnetosheath jet, which is in accordance with three observational jet
criteria and is caused by a SLAMS advecting towards the bow shock.
Research on Design Method of High Speed and High Dynamic Pressure Separation Structure
