Investigating the Source of the Slow Solar Wind Using Solar Orbiter Observations and the IRAP Solar Atmospheric Model

The slow solar wind can be separated into at least two different components: a dense, variable wind produced by helmet streamers and a more tenuous and Alfvénic component emitted by coronal holes. Previous studies have shown that the slow Alfvénic wind is associated with enhanced alpha particle abundances, strong proton beams, and large alpha-to-proton temperature ratios: typical properties of the fast wind known to originate from inside large coronal holes. Recent combined in-situ and remote-observation campaigns by the Solar Orbiter mission exploiting the Proton and Alpha particle Sensor (SWA-PAS) can help us to study the relationship between the Alfvénic slow wind and coronal holes. We exploit these latest observations in conjunction with the newly-developed multi-species IRAP Solar Atmospheric Model (ISAM) model to study the coronal conditions that favour the production of an Alfvénic slow wind. ISAM simulates the coupled transport of both neutral and charged particles between the chromosphere and the corona, including a self-consistent treatment of collisional and ionisation processes, as well as detailed energy and heat flux conservation equations. In this study we discuss how the simulated alpha to proton ratios are modulated in response to different coronal heating rates and discuss these simulation results in light of recent Solar Orbiter measurements. The results presented here were funded by the European Research Council through the SLOW SOURCE project grant number DLV-819189.