Abstract
. The injection of high repetition rate deuterium pellets is shown to trigger high-frequency edge localized modes (ELMs) in otherwise low natural ELM frequency H-mode deuterium discharges in the DIII-D tokamak. The resulting triggered ELMs have significantly lower energy and particle fluxes to the divertor than the natural ELMs. The plasma global energy confinement and density are not strongly affected by the pellet perturbations. The plasma core impurity density is strongly reduced with the application of the pellets. These experiments were performed in plasmas designed to match the ITER baseline configuration in shape and normalized β operation with input power just above the H-mode power threshold. This strongly reduced ELM intensity shows promise for exploitation in ITER to control ELM size while maintaining high plasma purity and performance.
