H-mode pedestal characteristics of SAS divertor discharges on DIII-D

The Small Angle Slot (SAS) divertor installed on DIII-D combines high closure with small incidence angle to achieve detachment over the entire divertor at low density. SAS discharges with BxgradB drift away from the X-point have improved energy confinement at a given pedestal density, n_e^PED, in comparison to an open divertor. SAS discharges have higher temperature and reduced thermal diffusivity from the top of the H-mode pedestal inwards for a given density. The higher T^PED is associated with a wider temperature pedestal with more of an outward shift of the n_e pedestal top relative to the T_e top. Both the SAS and open divertor configurations lie on the ballooning boundary for the peeling-ballooning mode at a similar normalized pressure gradient, but the pedestal width of the SAS discharge exceeds the EPED1.0 scaling by ~15%. Neon injection into a SAS discharge resulted in increased core Ti and rotation and increased pedestal pressure gradient associated with improved ballooning branch stability due to increased diamagnetic stabilization.