Identifying and Correcting Errors in Ambient Solar Wind Modeling

The solar wind expands outward from the solar corona, defining the interplanetary medium through which coronal mass ejections (CMEs) and solar energetic particles (SEPs) propagate. Accurate models of this ambient solar wind and its embedded magnetic fields are crucial for heliophysics and space weather research. Studies have highlighted the importance of ambient solar wind modeling for accurate CME arrival time predictions. However, comparisons of in situ spacecraft measurements to model solutions at L1 show that state-of-the-art models often perform comparably to a simplistic assumption that solar wind conditions at L1 repeat every 27 days. Here we study why state-of-the-art models often exhibit such surprisingly large errors. Going deeper than previous validation studies, we examine the physical reasons for erroneous predictions on an event-by-event basis by comparing imaging and in-situ observations with simulation results, and provide possible strategies to address these challenges. We study how magnetic structures at coronal hole boundaries, such as streamers and pseudo-streamers, affect model outcomes, among many other experiments. We also study how the choice of ADAPT maps could be crucial in the context of solar wind modelling. We demonstrate our recommendations for improving ambient solar wind modeling through the Wang-Sheeley-Arge (WSA) framework, as implemented by Reiss et al. (2019, 2020). Our findings highlight the different sources that could lead to erroneous predictions, how we can improve the predictions, and the critical need to better constrain magnetic models with observational data to enhance our ambient solar wind modeling capabilities. Moving forward, such improvements are vital for advancing the reliability of space weather forecasting, ultimately protecting astronauts and technological assets in space.