Impact of lithium pellets on plasma performance in the ASDEX Upgrade all-metal-wall tokamak

P. T. Lang, R. Maingi, D. K. Mansfield, R. M. McDermott, R. Neu, E. Wolfrum, R. Arredondo Parra, M. Bernert, G. Birkenmeier, A. Diallo, M. Dunne, E. Fable, R. Fischer, B. Geiger, Antti Hakola, V. Nikolaeva, A. Kappatou, F. Laggner, M. Oberkofler, B. PloecklS. Potzel, T. Pütterich, B. Sieglin, T. Szepesi

    Research output: Contribution to journalArticleScientificpeer-review

    7 Citations (Scopus)

    Abstract

    The impact of lithium (Li) on plasma performance was investigated at the ASDEX Upgrade tokamak, which features a full tungsten wall. Li pellets containing 1.6 × 1020 Li atoms were launched with a speed of 600 m s-1 to achieve deep penetration into the plasma and minimize the impact on the first wall. Homogeneous transient Li concentrations in the plasma of up to 15% were established. The Li sustainment time in the plasma decreased with an increasing heating power from 150 to 40 ms. Due to the pellet rate being restricted to 2 Hz, no Li pile-up could take place. No significant positive impact on plasma properties, as reported from other tokamak devices, could be found; the Li pellets rather caused a small reduction in plasma energy, mainly due to enhanced radiation. Due to pellet injection, a short-lived Li layer was formed on the plasma-facing components, which lasted a few discharges and led to moderately beneficial effects during plasma start-up. Most pellets were found to trigger type-I ELMs, either by their direct local perturbation or indirectly by the altered edge conditions; however, reliability was less than 100%.

    Original languageEnglish
    Article number016030
    JournalNuclear Fusion
    Volume57
    Issue number1
    DOIs
    Publication statusPublished - 1 Jan 2017
    MoE publication typeA1 Journal article-refereed

    Keywords

    • confinement
    • ELMs
    • Li pellets
    • plasma facing components
    • tokamak ASDEX upgrade

    Fingerprint Dive into the research topics of 'Impact of lithium pellets on plasma performance in the ASDEX Upgrade all-metal-wall tokamak'. Together they form a unique fingerprint.

  • Cite this

    Lang, P. T., Maingi, R., Mansfield, D. K., McDermott, R. M., Neu, R., Wolfrum, E., Arredondo Parra, R., Bernert, M., Birkenmeier, G., Diallo, A., Dunne, M., Fable, E., Fischer, R., Geiger, B., Hakola, A., Nikolaeva, V., Kappatou, A., Laggner, F., Oberkofler, M., ... Szepesi, T. (2017). Impact of lithium pellets on plasma performance in the ASDEX Upgrade all-metal-wall tokamak. Nuclear Fusion, 57(1), [016030]. https://doi.org/10.1088/0029-5515/57/1/016030