Authors: Gregory Szypko (Rice University), Stephen Bradshaw (Rice University), Grant Gorman (Sandia National Laboratories)

Interchange reconnection (IR) is a magnetic reconnection scenario occurring at the boundary between open- and closed-field regions of the solar atmosphere. IR presents a mechanism for “opening up” closed flux tubes, allowing formerly isolated plasma populations to intermix and potentially contributing to the high variability of the slow solar wind. To infer the prevalence of IR from observational data, it is crucial to understand the signatures this process may embed in the outflowing solar wind and in the extreme ultraviolet emissions of the corona. In the present study, we forward model the multi-species signatures of IR that may be observed by in-situ missions in the corona and solar wind.

We begin by performing numerical simulations of IR scenarios using a 2.5D resistive MHD (magnetohydrodynamic) model in our code SPRUCE. We then apply a novel post-processing pipeline that synthesizes multi-species observations of these MHD scenarios from the perspective of a simulated in-situ probe. To do so, we perform zero-dimensional multi-species non-LTE (local thermodynamic equilibrium) simulations for individual parcels of plasma as they move through the MHD simulation. These localized simulations, informed by the time-varying MHD conditions local to the parcel, model the time evolution of temperature and abundance for electrons as well as all of the elements and ionization states present in the corona. Segments of these time series are then stitched together as the corresponding parcels cross the time-varying location of the simulated in-situ probe. The result is synthetic in-situ observations of the 2.5D MHD simulation that account for the observed plasma’s source region(s) and the multi-species dynamics driven by the IR.

We discuss the implications of these results for interpreting in-situ measurements of coronal and solar wind plasma, and the applicability of this pipeline to synthesizing remote-sensing signatures of IR. Ultimately, this approach will help us understand the degree to which IR and other phenomena contribute to coronal energization and solar wind formation by improving our analyses of in-situ coronal and solar wind observations.