Impact of the Radiating Divertor Approach on Future Tokamaks*

We report on recent results that apply the deuterium/neon-based radiating divertor approach to three future tokamak concepts: (1) ITER Baseline plasmas, (2) AT high performance plasmas, and (3) H-mode plasmas that are isolated from their divertor targets (Super X-like). Analysis of H-mode plasmas in the ITER Baseline shape, characterized by $q_{95}=3.15$, $I/aB=1.4$, $\beta_N=2$ in the ITER shape, indicates significant a heat flux reduction ($\sim$2.5x) during both ELMing and between ELM periods and a factor of two increase in radiated power, almost all of which occurs in the divertor/SOL regions. Radiating divertor applied to AT plasmas (e.g., $\beta_N=3$ and $H_{89p}=2.4$) is shown to reduce heat flux at least 30\%, while at the same time maintaining high performance characteristics. We present our most recent results of studies designed to assess the value of increasing parallel connection length ($L_{||}$) of the outer divertor leg in a radiating divertor environment. Previous experiments have suggested that significant heat flux reduction at the OSP can be possible by increasing $L_{||}$.