Evolution of high-speed jets and plasmoids downstream of the
quasi-perpendicular bow shock
Abstract
Plasma structures with enhanced dynamic pressure, density or speed are
often observed in Earth’s magnetosheath. We present a statistical study
of these structures, known as jets and fast plasmoids, in the
magnetosheath, downstream of both the quasi-perpendicular and
quasi-parallel bow shocks. Using measurements from the four
Magnetospheric Multiscale (MMS) spacecraft and OMNI solar wind data from
2015–2017, we present observations of jets during different upstream
conditions and in the wide range distances from the bow shock. Jets
observed downstream of the quasi-parallel bow shock are seen to
propagate deeper and faster into the magnetosheath and on towards the
magnetopause. We estimate the shape of the structures by treating the
leading edge as a shock surface, and the result is that the jets are
elongated in the direction of propagation but also that they expand more
quickly in the perpendicular direction as they propagate through the
magnetosheath.