Wall conditioning with lithium evaporation

Sugai, Hideo; Toyoda, Hirotaka; Nakamura, Kohji; Furuta, K.; Ohori, Momoko; Toi, K.; Hirokura, S.; Sato, K.

doi:10.1016/0022-3115(94)00423-4

Cited by 57 publications

(37 citation statements)

References 4 publications

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“…However, unlike in TFTR, no significant confinement enhancement was reported in these devices, although the role of lithium to reduce impurities in the plasma was confirmed. In particular, the JIPP T-IIU experiments confirmed the ability of lithium to getter different types of impurities such as CO and CH 4 [8,9].…”

Section: Introductionmentioning

confidence: 83%

“…Using lithium pellet in combination with high power neutral beam injection enabled the TFTR tokamak to achieve high plasma performance [6]. Evaporating lithium to getter the inside walls of a tokamak was also done in the TdeV [7] and JIPP T-IIU tokamaks [8]. However, unlike in TFTR, no significant confinement enhancement was reported in these devices, although the role of lithium to reduce impurities in the plasma was confirmed.…”

Section: Introductionmentioning

confidence: 99%

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Plasma–lithium interaction in the CDX-U spherical torus

Antar

Doerner

Kaita

et al. 2002

Fusion Engineering and Design

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Results on the interaction between plasma in the current drive experiment-upgrade (CDX-U) spherical torus and a liquid lithium limiter are reported. It is observed that macroscopic lithium droplets detach from the limiter head and fall towards the plasma core. However, no disruptions occurred during these discharges despite the fact that relatively large-scale blobs are observed entering the confined plasma. A multi-tip Langmuir probe measures the edge plasma properties. It is found that the average density and temperature and their fluctuations are unaffected by the presence of lithium within experimental error.

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Section: Introductionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Plasma–lithium interaction in the CDX-U spherical torus

Antar

Doerner

Kaita

et al. 2002

Fusion Engineering and Design

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“…Our initial experiments applying D discharges to evaporated lithium surfaces demonstrate the effectiveness of the thin lithium coating pumping on deuterium-depleted graphite surfaces and the need for prompt application of the reference discharge. The lithium coatings used in these experiments appear sensitive not only to interactions with residual fuel gases in the graphite substrate but also to time after the deposition since interactions with vacuum vessel residual gas components (H 2 , D 2 H 2 0, D 2 O, N 2 , CO, and CO 2 ) and intercalation of the lithium into the graphite [5][6][7] can occur. These results are consistent with TFTR results [3] and laboratory experiments [5][6][7].…”

Section: Discussionmentioning

confidence: 99%

Effect of lithium PFC coatings on NSTX density control

Kugel

Bell

et al. 2007

Journal of Nuclear Materials

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Lithium coatings on the graphite plasma facing components (PFCs) in NSTX are being investigated as a tool for density profile control and reducing the recycling of hydrogen isotopes. Repeated lithium pellet injection into Center Stack Limited and Lower Single Null Ohmic Helium Discharges were used to coat graphite surfaces that had been pre-conditioned with Ohmic Helium Discharges of the same shape to reduce their contribution to hydrogen isotope recycling. The following deuterium NBI reference discharges exhibited a reduction in density by a factor of about 3 for limited and 2 for diverted plasmas respectively, and peaked density profiles. Recently, a lithium evaporator has been used to apply thin coatings on conditioned and unconditioned PFCs. Effects on the plasma density and the impurities were obtained by pre-conditioning the PFCs with ohmic helium discharges, and performing the first deuterium NBI discharge as soon as possible after applying the lithium coating.

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“…[2][3][4][5][6] The fluid character, as well as the magnetohydrodynamics (MHD) features of molten salts and liquid metals, especially liquid lithium, have been intensively investigated by the APEX team using simulation and laboratory experiments. 7 Also, related experiments were conducted in some tokamak devices, such as: TFTR, [8][9][10][11][12][13] TdV, 12 CDX-U, 14 FTU 15 and DIII-D. 16 The lithium divertor/wall showed a number of advantages for removing incident tritium and impurity effluxes, providing a self-healing plasma facing surface in a diverted high power DT reactor, 7,17,18 and enabling a lithium wall fusion regime. 19 Increases in the electron temperature, decreases in recycling and resulting control over the plasma density, suppression of ELMs, and a strong reduction in the plasma resistivity were observed in the lithium experiments.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of energy transport of Li-conditioned and non-Li-conditioned plasmas in the National Spherical Torus Experiment (NSTX)

Ding

Kaye

Bell

et al. 2009

Plasma Phys. Control. Fusion

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The transport properties of NSTX plasmas obtained during the 2008 experimental campaign have been studied and are reported here. Transport trends and dependences have been isolated, and it is found that both electron and ion energy transport coefficients have strong dependences on local values of n∇T , which in turn is strongly dependent on local current density profile. Without identifying this dependence, it is difficult to identify others, such as the dependence of transport coefficients on B p (or q), I p and P heat . In addition, a comparison between discharges with and without Lithium wall conditioning has been made. While the trends in the two sets of data are similar, the thermal transport loss, especially in the electron channel, is found to strongly depend on the amount of Lithium deposited, decreasing by up to 50% of its no-Lithium value.

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Wall conditioning with lithium evaporation

Cited by 57 publications

References 4 publications

Plasma–lithium interaction in the CDX-U spherical torus

Plasma–lithium interaction in the CDX-U spherical torus

Effect of lithium PFC coatings on NSTX density control

Characteristics of energy transport of Li-conditioned and non-Li-conditioned plasmas in the National Spherical Torus Experiment (NSTX)

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