H-mode access in ITER-relevant electron-heat-dominated plasmas
2025 Research Campaign, Turbulence and Transport
Purpose of Experiment
This experiment seeks to measure the input power requirements necessary for accessing high confinement mode (H-mode) at the DIII-D tokamak in low density, electron heat dominant conditions. This regime, previously inaccessible due to a lack of sufficient electron cyclotron heating power, will provide data that directly informs ITER’s first run campaign. The experiment will acquire detailed edge turbulence and profile measurements, with particular emphasis on the evolution of the edge radial electric field, whose shear profile is believed to trigger the transition from low to high confinement mode (L-H transition). The experiment will additionally acquire novel measurements of both toroidal and poloidal Reynolds stress, supporting the development of reduced models for predicting the L-H power threshold. Under these ITER-like conditions, the impact of high-Z radiators will be assessed using Ne, Ar, and Mo injection to mimic radiation conditions anticipated in ITER plasmas with W plasma facing component contamination.