Advancing SOLPS-ITER validation with TCV L-mode discharges

This work advances the quantitative validation of SOLPS-ITER against TCV ohmic L-mode discharges. It demonstrates that the treatment of the ion parallel heat-flux limiter and the assumptions adopted for chemical sputtering provide a consistent explanation for the divertor over-cooling and excessive divertor density predicted by earlier simulations. A systematic heat-flux-limiter scan highlights that a strong restriction of ion heat conduction significantly reduces both electron target temperatures T e,t and ion target temperatures T i,t , while driving a compensating increase in plasma density n e,t , resulting in an overly cold and dense divertor solution. The availability of new T e and T i measurements along the outer divertor leg of TCV further constrains the model and supports the use of a weakly limited ion heat flux to best reproduce experimental observations. Restricting chemical sputtering to tiles in the immediate vicinity of the strike points suppresses a spurious low-field-side carbon source associated with thermal molecules and significantly improves agreement with two-dimensional CIII emissivity reconstructions. The resulting SOLPS-ITER setup achieves improved simultaneous agreement across multiple diagnostics for upstream, divertor-leg, and target electron density and temperature profiles, as well as for target heat-flux and radiation measurements.