@article{31,
  author = {Florian Effenberg},
  title = {Mitigation of plasma{\textendash}wall interactions with low-Z powders in DIII-D high confinement plasmas},
  abstract = {<p>Experiments with low-Z powder injection in DIII-D high confinement discharges demonstrated increased divertor dissipation and detachment while maintaining good core energy confinement. Lithium (Li), boron (B), and boron nitride (BN) powders were injected in H-mode plasmas (<em>I</em><sub>p</sub>\&nbsp;= 1 MA,\&nbsp;<em>B</em><sub>t</sub>\&nbsp;= 2\&nbsp;T,\&nbsp;<em>P</em><sub>NB</sub>\&nbsp;= 6\&nbsp;MW, ⟨<em>n</em><sub>e</sub>⟩ = 3.6{\textendash}5.0 . 10<sup>19</sup>\&nbsp;m<sup>-3</sup>) into the upper small-angle slot divertor for 2\&nbsp;s intervals at constant rates of 3{\textendash}204 mg s<sup>-1</sup>. The multi-species BN powders at a rate of 54 mg s<sup>-1</sup>\&nbsp;showed the most substantial increase in divertor neutral compression by more than an order of magnitude and lasting detachment with minor degradation of the stored magnetic energy\&nbsp;<em>W</em><sub>mhd</sub>\&nbsp;by 5\%. Rates of 204 mg s<sup>-1</sup>\&nbsp;of boron nitride powder further reduce edge localized mode-fluxes on the divertor but also cause a drop in confinement performance by 24\% due to the onset of an\&nbsp;<em>n</em>\&nbsp;= 2 tearing mode. The application of powders also showed a substantial improvement of wall conditions manifesting in reduced wall fueling source and intrinsic carbon and oxygen content in response to the cumulative injection of non-recycling materials. The results suggest that low-Z powder injection, including mixed element compounds, is a promising new core-edge compatible technique that simultaneously enables divertor detachment and improves wall conditions during high confinement operation.</p>
},
  year = {2022},
  journal = {Nuclear Fusion},
  volume = {62},
  chapter = {106015},
  month = {08/2022},
  url = {https://dx.doi.org/10.1088/1741-4326/ac899d},
  doi = {10.1088/1741-4326/ac899d},
}