Multi-spacecraft Observations of Reconnection in a Turbulent ICME Sheath

Coronal mass ejections propagating in the interplanetary space with speeds greater than the ambient solar wind, produce a shock wave ahead of them. Confined behind the shock and ahead of the magnetic ejecta, forms a very turbulent sheath region from the compressed and heated solar wind plasma. At L1, the sheath region of an Interplanetary Coronal Mass Ejection (ICME) is characterized by strong and short-lived directional changes in the magnetic field and plasma velocity, and high plasma beta. Here, we investigate small-scale (minutes) current sheets detected simultaneously by WIND, ACE and DSCOVR during the 8 Sep 2017 ICME. We observe signatures of reconnection in some of the current sheets, such as changes in magnetic field topology, plasma outflows, and plasma heating. The solar wind monitors were well positioned along the Sun-Earth line, allowing us to track the evolution of these small-scale structures. We present evidence of magnetic field reorganization in the same structure identified by the three spacecraft. Such change of the magnetic field direction due to reconnection could provide a physical mechanism for altering the potential geoeffectivity of a CME.