Mixed Source Region Signatures inside Magnetic Switchback Patches Inferred by Heavy Ion Diagnostics

Abstract Since Parker Solar Probe’s (Parker’s) first perihelion pass at the Sun, large-amplitude Alfvén waves grouped in patches have been observed near the Sun throughout the mission. Several formation processes for these magnetic switchback patches have been suggested with no definitive consensus. To provide insight into their formation, we examine the heavy ion properties of several adjacent magnetic switchback patches around Parker’s 11th perihelion pass, capitalizing on a spacecraft lineup with Solar Orbiter where each samples the same solar wind streams over a large range of longitudes. Heavy ion properties (Fe/O, C 6+ /C 5+ , O 7+ /O 6+ ) related to the wind’s coronal origin, measured with Solar Orbiter, can be linked to switchback patch structures identified near the Sun with Parker. We find that switchback patches do not contain distinctive ion and elemental compositional signatures different from the surrounding nonswitchback solar wind. Both the patches and ambient wind exhibit a range of fast and slow wind qualities, indicating coronal sources with open and closed field lines in close proximity. These observations and modeling indicate switchback patches form in coronal hole boundary wind and with a range of source region magnetic and thermal properties. Furthermore, the heavy ion signatures suggest interchange reconnection and/or shear-driven processes may play a role in their creation.