Dataset of ion flows and magnetic fields in magnetopause reconnection

In this study, we utilize in-situ data from MMS to explore the profiles of ion flows and magnetic fields within the exhaust region of magnetopause reconnection from October 2015 to April 2023. Specifically, we focus on magnetopause reconnection events that are associated with a southward interplanetary magnetic field (IMF). These reconnection events are anticipated to be of global scale by multi-point observations of ACE and THEMIS-B near 1 AU. Our analysis examines the dependence of ion flow and magnetic field characteristics on the upstream magnetosheath Alfvén Mach number (MA,sh). Our database include the characteristics of magnetic fields and ion flows across the magnetopause reconnection current layer. Magnetopause reconnection with low MA,sh is more concentrated near the subsolar point, while reconnection with high MA,sh is more evenly distributed in magnetic local time (MLT). Additionally, the magnetic field reversal across the magnetopause current layer is larger in cases of low MA,sh. Deflective flows around the magnetopause are stronger during high MA,sh magnetopause reconnection. In both high and low MA,sh scenarios, the high-speed reconnection outflow is mostly located on the magnetosphere side of the magnetopause current layer, with outflow velocities peaking close to the upstream Alfvén speed. Notably, ion flows exhibit significant variability when MA,sh is high, while magnetic fields show substantial variability when MA,sh is low. Our results provide insights into the upstream condition and structures of magnetopause reconnection.