Plasma-material interaction studies on lithium and lithiated substrates during compact tokamak operation

M. Nieto, Jean Paul Allain, A. Hassanein, V. Titov, M. Hendricks, T. Gray, R. Kaita, H. Kugel, R. Majeski, D. Mansfield, J. Spaleta, J. Timberlake

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

The role of lithium on the modification of recycling regimes in fusion reactors has renewed interest of previous lithium supershot experiments carried out in TFTR. There is a need to understand the interaction between edge plasmas and lithiated plasma-facing components (PFCs), which have the potential of enabling fusion reactors to operate at low-recycling regimes. The Interaction of Materials with Particles and Components Testing (IMPACT) facility at Argonne National Laboratory is currently collaborating with Princeton Plasma Physics Laboratory (PPPL) to conduct lithiated surface studies for the National Spherical Tokamak Experiment (NSTX) and the Current Drive eXperiment - Upgrade (CDX-U). IMPACT has the necessary tools to perform experiments that diagnose the surface dynamics of lithium thin films on metallic and non-metallic substrates, and can be monitored with multiple in-situ techniques (LEISS, AES, QMS and XPS) capturing real-time surface dynamics. Therefore, these techniques are available during He+ and D+ irradiation. Surface sputtering measurements can be performed using a quartz crystal microbalance - dual crystal unit (QCM-DCU) with very high sensitivity. Initial results suggest that lithium intercalation into graphite occurs quite rapidly and only a fraction lithium can be kept on the surface. On metallic substrates this intercalation is absent. Additional results of Li/metal systems show lithium surface self-healing with temperature. It was also found that the presence of lithium seems to inhibit hydrocarbon formation during D+ bombardment of graphite. Experiments in CDX-U have tested the effect of both solid and liquid lithium PFCs on tokamak plasmas, and significant changes in tokamak operation are observed. These include a strong reduction in both recycling and impurity levels in the gas phase, lowered loop voltage during ohmic operation, and an increased electron temperature at the edge.

Original languageEnglish (US)
Title of host publicationPLASMA AND FUSION SCIENCE
Subtitle of host publication16th IAEA Technical Meeting on Research using Small Fusion Devices; XI Latin American Workshop on Plasma Physics
Pages78-82
Number of pages5
DOIs
StatePublished - Dec 1 2006
EventPLASMA AND FUSION SCIENCE: 16th IAEA Technical Meeting on Research using Small Fusion Devices; XI Latin American Workshop on Plasma Physics - Mexico-City, Mexico
Duration: Nov 30 2006Dec 9 2006

Publication series

NameAIP Conference Proceedings
Volume875
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

ConferencePLASMA AND FUSION SCIENCE: 16th IAEA Technical Meeting on Research using Small Fusion Devices; XI Latin American Workshop on Plasma Physics
CountryMexico
CityMexico-City
Period11/30/0612/9/06

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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