Speaker
Description
Despite its role as the primary model for mapping solar wind sources, the Potential Field Source Surface (PFSS) model consistently fails to replicate the observed boundaries and internal topologies of coronal holes (CHs). To address this, we present a comprehensive statistical analysis of 702 observed CHs from 2010–2019, contrasting their PFSS-modeled magnetic structure with those of Quiet Sun (QS) regions.
Our results reveal a distinct low-altitude magnetic signature within CH boundaries: low-lying loops that are statistically narrower and lower than in the QS, with a median height that is strongly correlated to the mean magnetic flux density (cc = 0.81) in CHs, a relationship not present in QS areas. This suggests that CH magnetic topology is highly sensitive to local flux variations, which is often lost in global extrapolations. We also identify a distinct population of loops within CHs that reach high into the corona. This suggests that a single, global source surface radius (R_ss) is fundamentally inadequate for capturing CH connectivity.
Critically, we find that the model retains distinct structural differences between CH and QS regions even when it fails to predict open flux. Our results demonstrate that the mismatch between models and observations stems from inherent modeling limitations rather than observational error. To better capture the observed open field structure while maintaining computational efficiency, future modeling efforts should transition toward spatially-adaptive or non-uniform source surfaces that respond to local magnetic configurations.