Investigations of H-mode plasmas triggered directly by pellet injection in the DIII-D tokamak

The transition from low-confinement (L-mode) to high-confinement (H-mode) was experimentally studied. The experiments utilize pellet injection to provide significant results in several areas of H-mode physics. The H-mode power threshold was reduced by more than 23%. Further, the experimental edge local parameters at the H-mode transition were found to be in disagreement with predictions of various H-mode transition theories.