Topical Discussion Meeting - Coronal model validation for space-weather applications

More and more space-weather forecasting facilities rely on modelling chains to anticipate large-scale structures of the solar wind as well as coronal mass ejection propagations (ex: EUHFORIA, Enlil, SWMF, SUSANOO...). All of these structures rely heavily on the first part of the chain, namely the modelling of the solar corona, which will determine the open and closed field lines configuration critical to coronal holes as well as solar wind acceleration. The problem is that these models are usually not validated on their own, only by coupling with heliospheric models and with in situ validation with data at Earth. We want to raise the question of how to provide better constraints on coronal models, to ensure they deliver the right structures for space-weather applications. In this panel session, we will drive an open discussion about first benchmarking aspects (how do we define a proper benchmark case? how do we define operational time? what tricks can we share to improve convergence/accuracy? which minimal physics do model need? which physics is actually not relevant for space-weather?), and then which observations amd procedures are better suited for validation of coronal models on their own (can we define universal metrics for all the coronal/solar wind models? how do we evaluate magnetic field lines in a quantitative way with WL images? what about the impact of the input magnetogram? how do we standardize comparison with IPS data?).