A Case for a Switchback Generated by Interchange Reconnection Between the Open Solar Wind and Closed Magnetosphere Field Line

Abstract The Magnetospheric Multiscale mission observed a reconnecting current sheet within the magnetosheath, revealing its connection to a larger structure containing both magnetosheath and magnetospheric plasma. This structure exhibited a gradual rotation before reverting to its original orientation, with high‐energy electrons aligned with the magnetic field, indicating magnetospheric influence. The trailing edge of the structure hosted a reconnecting current sheet with a guide field strength of 1.2 and a bifurcated current sheet. The observed structure appears to be the result of dayside magnetospheric reconnection, where an open field line twisted upon itself, creating the local current sheet. We confirm that the structure qualifies as a magnetic switchback, a phenomenon commonly found in the solar wind due to the structure meeting criteria via the z‐parameter quantifying angular rotation exceeded 0.5 within the structure. This magnetic switchback was formed via interchange reconnection at the interface between open magnetosheath and closed magnetospheric field lines. These findings suggest that switchbacks can arise from reconnection at the solar wind‐magnetosphere boundary, offering new insights into transient plasma structures in planetary magnetospheres, as well as a means of studying similar physics in the solar corona without the need to directly enter the corona with the Parker Solar Probe.