Neoclassical Ti screening of tungsten in pedestal of hybrid steady-state scenario with grassy ELMs
2024 Research Campaign, Task Force: W Compatible Steady State Scenarios
Purpose of Experiment
The purpose of this experiment is to investigate the ion temperature screening of high-Z impurities in low-collisionality pedestal of Steady-State Hybrid scenario with grassy ELMs. Particularly with the new ITER plans for full tungsten wall, the understanding to tungsten transport is more important than ever. Impurity transport in the edge transport barrier (ETB) of regular H-mode plasmas is expected to be neoclassical , with a significant inward pinch proportional to impurity charge and driven by a negative gradient of ion density. Broad density pedestal observed in grassy elm regime and high ion temperatures, might increase the importance of outward temperature impurity screening, resulting in flt or hollow W density profiles in the pedestal.