A Current Sheet With Reconnection Signatures at a Magnetosheath Jet‐Driven Bow Wave

Abstract High‐speed jets are dynamic pressure enhancements in planetary magnetosheaths that carry energy, modify magnetic field topology, and may facilitate particle energization. These jets can generate bow waves by compressing ambient plasma at their leading edges. However, the effects of jet‐driven bow waves on magnetosheath current sheet properties and associated particle energization remain unclear. In this paper, Magnetospheric Multiscale (MMS) observations reveal a high‐speed jet in Earth's magnetosheath that drives an earthward bow wave at its leading edge. In the compressed foot region of this bow wave, we identify a current sheet showing ion‐coupled magnetic reconnection signatures, including electron and ion flows, electron energization, Ohmic heating, Hall field signatures, and rapid changes in magnetic topology and electron velocity distribution functions. These results shed new light on the role of jet‐driven magnetosonic compression in thin current sheet formation, reconnection‐related energy conversion, and particle energization in planetary sheath regions and compressed solar wind.