"Mitigation of plasma–wall interactions with low-Z powders in DIII-D" published

PPPL scientists conducted experiments with injecting low-Z (low atomic number) powders into plasmas in the DIII-D tokamak. They found that injecting powders such as lithium, boron, and boron nitride into the divertor region of the tokamak can enhance the dissipation and promote detachment of the  boundary plasma, while maintaining good energy confinement in the core plasma. The boron nitride powder was found to be the most effective, leading to a substantial increase in divertor neutral compression and lasting detachment with minimal degradation of the stored magnetic energy. However, at higher injection rates, there was a drop in confinement performance due to the onset of a tearing mode. Additionally, the injection of powders improved the condition of the tokamak wall, reducing the fueling source and the amount of carbon and oxygen buildup. Overall, the results suggest that low-Z powder injection is a promising technique for improving tokamak performance.

The paper has been published in Nuclear Fusion: F. Effenberg et al 2022 Nucl. Fusion 62 106015 DOI 10.1088/1741-4326/ac899d    

Find preprint on arXiv:2203.15204 [physics.plasm-ph]