Rotational discontinuity-generated magnetosheath jets at Earth's quasi-perpendicular bow shock: Results from a hybrid-Vlasov simulation

In this study we investigate the formation of magnetosheath jets before, during, and after the interaction between Earth's bow shock and a solar wind rotational discontinuity in a 2D ecliptic simulation run of the global magnetospheric hybrid-Vlasov model Vlasiator. Magnetosheath jets are transient enhancements of dynamic pressure downstream of collisionless shocks, and they have been observed in Earth's magnetosheath, the magnetosheaths of other planets, as well as the sheaths of interplanetary shocks. Rotational discontinuities (RD) are boundaries where the components of the magnetic field and velocity tangential to the boundary change abruptly, and they have been observed by spacecraft in the solar wind and in Earth's magnetosheath. Both spacecraft observations and previous simulation studies have shown that RDs interacting with the bow shock can generate dynamic pressure pulses in the magnetosheath.

Studying magnetosheath jets is important because they have been shown to potentially have magnetospheric effects if impacting the magnetopause, and while travelling through the magnetosheath they can modify its properties. Statistical studies of simulations and spacecraft observations have shown that jets tend to form mainly at Earth's quasi-parallel bow shock, that is where the interplanetary magnetic field (IMF) direction is nearly parallel to the shock normal, but they have also been observed downstream of the quasi-perpendicular shock. By studying the formation and properties of jets at the quasi-parallel and quasi-perpendicular shock at different times in the simulation, we aim to shed light on the differences between jets forming at different parts of the shock, and during different stages of interaction between an RD and the bow shock.