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. Ploeckl & 4 others S. Potzel, T. Pütterich, B. Sieglin, T. Szepesi

Research output: Contribution to journalArticleScientificpeer-review

6 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

Fingerprint

pellets
lithium
metals
tokamak devices
piles
tungsten
penetration
actuators
injection
perturbation
heating
radiation
atoms

Keywords

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

Cite this

Lang, P. T., Maingi, R., Mansfield, D. K., McDermott, R. M., Neu, R., Wolfrum, E., ... 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
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, Antti ; Nikolaeva, V. ; Kappatou, A. ; Laggner, F. ; Oberkofler, M. ; Ploeckl, B. ; Potzel, S. ; Pütterich, T. ; Sieglin, B. ; Szepesi, T. / Impact of lithium pellets on plasma performance in the ASDEX Upgrade all-metal-wall tokamak. In: Nuclear Fusion. 2017 ; Vol. 57, No. 1.
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title = "Impact of lithium pellets on plasma performance in the ASDEX Upgrade all-metal-wall tokamak",
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{\%}.",
keywords = "confinement, ELMs, Li pellets, plasma facing components, tokamak ASDEX upgrade",
author = "Lang, {P. T.} and R. Maingi and Mansfield, {D. K.} and McDermott, {R. M.} and R. Neu and E. Wolfrum and {Arredondo Parra}, R. and M. Bernert and G. Birkenmeier and A. Diallo and M. Dunne and E. Fable and R. Fischer and B. Geiger and Antti Hakola and V. Nikolaeva and A. Kappatou and F. Laggner and M. Oberkofler and B. Ploeckl and S. Potzel and T. P{\"u}tterich and B. Sieglin and T. Szepesi",
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Lang, PT, Maingi, R, Mansfield, DK, McDermott, RM, 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, Ploeckl, B, Potzel, S, Pütterich, T, Sieglin, B & Szepesi, T 2017, 'Impact of lithium pellets on plasma performance in the ASDEX Upgrade all-metal-wall tokamak', Nuclear Fusion, vol. 57, no. 1, 016030. https://doi.org/10.1088/0029-5515/57/1/016030

Impact of lithium pellets on plasma performance in the ASDEX Upgrade all-metal-wall tokamak. / 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, Antti; Nikolaeva, V.; Kappatou, A.; Laggner, F.; Oberkofler, M.; Ploeckl, B.; Potzel, S.; Pütterich, T.; Sieglin, B.; Szepesi, T.

In: Nuclear Fusion, Vol. 57, No. 1, 016030, 01.01.2017.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Impact of lithium pellets on plasma performance in the ASDEX Upgrade all-metal-wall tokamak

AU - Lang, P. T.

AU - Maingi, R.

AU - Mansfield, D. K.

AU - McDermott, R. M.

AU - Neu, R.

AU - Wolfrum, E.

AU - Arredondo Parra, R.

AU - Bernert, M.

AU - Birkenmeier, G.

AU - Diallo, A.

AU - Dunne, M.

AU - Fable, E.

AU - Fischer, R.

AU - Geiger, B.

AU - Hakola, Antti

AU - Nikolaeva, V.

AU - Kappatou, A.

AU - Laggner, F.

AU - Oberkofler, M.

AU - Ploeckl, B.

AU - Potzel, S.

AU - Pütterich, T.

AU - Sieglin, B.

AU - Szepesi, T.

PY - 2017/1/1

Y1 - 2017/1/1

N2 - 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%.

AB - 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%.

KW - confinement

KW - ELMs

KW - Li pellets

KW - plasma facing components

KW - tokamak ASDEX upgrade

UR - http://www.scopus.com/inward/record.url?scp=85009813254&partnerID=8YFLogxK

U2 - 10.1088/0029-5515/57/1/016030

DO - 10.1088/0029-5515/57/1/016030

M3 - Article

VL - 57

JO - Nuclear Fusion

JF - Nuclear Fusion

SN - 0029-5515

IS - 1

M1 - 016030

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Lang PT, Maingi R, Mansfield DK, McDermott RM, Neu R, Wolfrum E et al. Impact of lithium pellets on plasma performance in the ASDEX Upgrade all-metal-wall tokamak. Nuclear Fusion. 2017 Jan 1;57(1). 016030. https://doi.org/10.1088/0029-5515/57/1/016030