Drift effects on the tokamak power scrape-off width*

Recent experimental analysis suggests that the scrape-off layer (SOL) heat flux width ($\lambda_{\mathrm{q}})$ for ITER will be near 1 mm, sharply narrowing the planned operating window. In this work, motivated by the heuristic drift (HD) model, which predicts the observed inverse plasma current scaling, SOLPS-ITER is used to explore drift effects on $\lambda _{\mathrm{q}}$. Modeling focuses on an H-mode DIII-D discharge. In initial results, target recycling is set to 90{\%}, resulting in sheath-limited SOL conditions. SOL particle diffusivity (D$_{\mathrm{SOL}})$ is varied from 0.1 to 1 m$^{\mathrm{2}}$/s. When drifts are included, $\lambda_{\mathrm{q}}$ is insensitive to D$_{\mathrm{SOL}}$, consistent with the HD model, with $\lambda_{\mathrm{q}}$ near 3 mm; in no-drift cases, $\lambda _{\mathrm{q}}$ varies from 2 to 5 mm. Drift effects depress near-separatrix potential, generating a channel of strong electron heat convection that is insensitive to D$_{\mathrm{SOL}}$. Sensitivities to thermal diffusivities, plasma current, toroidal magnetic field, and device size are also assessed. These initial results will be discussed in detail, and progress toward modeling experimentally relevant high-recycling conditions will be reported.