Parker Solar Probe Observations of a Flux Rope Embedded in a Near-Sun Heliospheric Current Sheet Magnetic Reconnection Exhaust

Abstract In situ observations by Parker Solar Probe (PSP) suggest that the heliospheric current sheet (HCS) undergoes near-continuous magnetic reconnection close to the Sun, in stark contrast to scarce observations of this phenomenon in the HCS at 1 au. Situated at the boundary between sectors of opposite interplanetary magnetic field polarity, reconnection in the HCS has important consequences for magnetic topology and plasma dynamics in the slow solar wind. We report observations of a reconnection outflow in the HCS near the Alfvén transition region in PSP’s 17th solar encounter, featuring plasma jetting, proton temperature enhancement, and electron heat flux dropout. Embedded within the exhaust is a non-force-free flux rope plasmoid exhibiting counterstreaming strahl electrons, indicating connection at both ends to the Sun in an otherwise disconnected region of the magnetic field. The flux rope features diminished isotropic proton temperature and lower bulk speed compared to the remainder of the HCS exhaust. Its oblique orientation and different plasma properties imply that the flux rope originates from a different reconnection site to the HCS exhaust, suggesting PSP has intercepted a flux-rope-like streamer blob produced at the helmet streamer. Remote observations show several comparable blobs traveling in a distant coronal ray, demonstrating the possibility that the in situ flux rope is a streamer blob. The combination of in situ and remote observations demonstrates the role of magnetic reconnection in HCS dynamics, contributing to a growing understanding of this fundamental mechanism and its impact on the young solar wind.