Magnetosheath jets: morphology and evolution from multi-spacecraft observations

Plasma structures with the enhanced dynamic pressure, density, and/or bulk speed, commonly referred to as magnetosheath (MSH) jets, can be detected downstream of both quasi-perpendicular and quasi-parallel bow shocks. Although their presence in the MSH is well established, their true three-dimensional morphology, internal structure, and characteristic scales remain under active debate. Recent simulation results, suggesting filamentary interconnected jet structures, contrast with the simplified “pancake” or cylindrical geometries often inferred from single-spacecraft observations, highlighting the need of multi-point studies.

We present case studies of complex structure of MSH jets using coordinated measurements of THEMIS, MMS, and other missions. We focus on their spatial structure and temporal evolution as they propagate through the MSH, with attention to multi-spacecraft signatures in plasma and magnetic field parameters. Rather than drawing general conclusions, this work aims to illustrate the capabilities and limitations of multi-spacecraft observations for determination of jet morphology and evolution. We try to place individual events into the broader context of ongoing discussions. Particular attention is given to the interaction of the MSH jet with the magnetopause and its role in (localized) boundary dynamics.