Assessing the Role of Interchange Reconnection in Forming Switchbacks

Abrupt deflections of the magnetic field in the solar wind, so called "switchbacks," are frequently observed by the Parker Solar Probe (PSP) during its first two orbits and are believed to play an important role in unveiling the nature of solar corona heating and solar wind acceleration in the inner heliosphere. Many attempts were made recently to understand the nature of switchbacks. However, the origin, propagation, and evolution of switchbacks are still under debate. In this study, we attempt to use the linear theory of Zank et al. to interpret the switchback observations. We select 96 simple one-humped switchback events during the first encounter of PSP and use a Markov Chain Monte Carlo technique to fit the observed magnetic field and plasma variables with the model predictions for each event. The chi-squared goodness-of-fit test is used to evaluate the fittings. We find that about 47.9% and 42.7% of the events are accepted as good fits below the 95% and 90% critical values, respectively. This statistical study validates the reliability of the linear theory of Zank et al. for a significant number of switchback events. The statistical analysis provides the most probable initial conditions for switchbacks generated by interchange reconnection, which provides insight into the environment at which interchange reconnection was occurring.