Explore ELM-free enhanced pedestal access via low-Z impurity powder injection with adaptive RMP control?

2024 Research Campaign, Core-Edge Integration

Purpose of Experiment

This experimental proposal investigates the extension of enhanced pedestal H-mode (EH) through low-Z powder injection combined with a new adaptive beta_N feedback RMP control system in the DIII-D tokamak. Low-Z injection, such as lithium in powder form, induces a bifurcation to higher pedestal pressure and width. However, ELMs occur when discharge reaches the peeling-ballooning limit. By modulating the pedestal dynamics via beta_N feedback, the adaptive RMP controller aims to maintain a Li-induced ELM-free EH mode over extended periods. This study provides innovative control tools and is poised to facilitate access to a novel, stationary, high-confinement mode.

Experimental Approach

This study seeks to demonstrate the practical application of these techniques to reliably suppress ELMs and maintain high pedestal conditions, addressing a significant challenge in fusion energy research toward commercially viable energy production.

See more details, including project leads, at U.S. Department of Energy, Office of Scientific and Technical Information (OSTI).