Particle Transport in RMP ELM Suppressed H-modes

Suppression of Type I ELMS with $n$=3 edge resonant magnetic perturbations (RMP) depends on reducing the pedestal pressure gradient below the peeling-ballooning mode stability limit. This pressure gradient reduction results from a reduction in pedestal particle density and effective particle confinement time $\tau _{p}$*. Recent experimental results suggest that this $\tau _{p}$* reduction arises from at least two mechanisms: increased ion-scale turbulence in the region 1$>$r/a$>$0.75, and improved coupling of the plasma to the pump due to strike point splitting. These mechanisms are observed to increase the density at the pump entrance, leading to improved pumping efficiency and lower $\tau _{p}$*.