Enhancement of Tokamak Fusion Test Reactor performance by lithium conditioning

Mansfield, D. K.; Hill, K. W.; Strachan, J.D.; Bell, M.G.; Scott, S. D.; Budny, R.; Marmar, E.; Snipes, J. A.; Terry, J. L.; Batha, S. H.; Bell, R. E.; Bitter, M.; Bush, C. E.; Chang, Z.; Darrow, D. S.; Ernst, D. R.; Fredrickson, E. D.; Grek, B.; Herrmann, H. W.; Janos, A.; Jassby, D.L.; Jobes, F. C.; Johnson, D.; Johnson, L. C.; Levinton, F. M.; Mikkelsen, D. R.; Mueller, D.; Owens, D. K.; Park, H.; Ramsey, A. T.; Roquemore, A. L.; Skinner, C.H.; Stevenson, T. N.; Stratton, B. C.; Synakowski, E. J.; Taylor, G.; Halle, A. von; Goeler, S. von; Wong, K. L.; Zweben, S. J.

doi:10.1063/1.871984

Cited by 177 publications

(85 citation statements)

References 10 publications

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“…A decrease of electron density from discharge to discharge during tokamak operation with lithium was observed earlier on deuterium [4,9]. In our experiments we have detected a similar appearance on helium too (Fig.…”

Section: Lithium Getter Effects On T-11msupporting

confidence: 73%

Technological aspects of lithium capillary-pore systems application in tokamak device

Evtikhin¹,

Lyublinski²,

Vertkov³

et al. 2001

Fusion Engineering and Design

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The paper concerns two problems. First, the usage of a lithium material basing on capillary-pore systems as a material of rail limiter working in conditions of considerable thermal ( 10 MW/m 2 ) and electromechanical loads caused by interaction with a tokamak plasma in a T-11M tokamak. The second problem is the influence of a modification of recycling for hydrogen, deuterium and helium due to lithium sputtering and deposition on the discharge conditions.

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Section: Lithium Getter Effects On T-11msupporting

confidence: 73%

Technological aspects of lithium capillary-pore systems application in tokamak device

Evtikhin¹,

Lyublinski²,

Vertkov³

et al. 2001

Fusion Engineering and Design

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“…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].…”

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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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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“…This deposition was carried out in earlier experiments by the injection and ablation of a few small (3 mg each) Li pellets [3,4,5,6]. In order to improve plasma performance during NBI, Li pellets were typically injected into the Ohmic phase of discharges and the ablated Li was allowed to 3 condense out of the plasma column and onto the limiter surface before the application of auxiliary heating.…”

Section: Introductionmentioning

confidence: 99%

“…It should be noted that the DOLLOP experiments were carried out with Li 6 , instead of natural Li 7 , in order to accommodate RFheating experiments that were carried out contemporaneously on TFTR. The RF experiments were intended to heat Deuterium ions resonantly.…”

mentioning

confidence: 99%

Observations concerning the injection of a lithium aerosol into the edge of TFTR discharges

et al. 2001

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A new method of actively modifying the plasma-wall interaction was tested on the Tokamak Fusion Test Reactor. A laser was used to introduce a directed lithium aerosol into the discharge scrape-off layer. The lithium introduced in this fashion ablated a n d migrated preferentially to the limiter contact points. This allowed the plasma-wall interaction to be influenced in situ and in real t i m e by external means. Significant improvement in energy confinement and fusion neutron production rate as well as a reduction in t h e plasma Z eff have been documented in a neutral-beam-heated plasma. The introduction of a metallic aerosol into the plasma e d g e increased the internal inductance of the plasma column and also resulted in prompt heating of core electrons in Ohmic plasmas. Preliminary evidence also suggests that the introduction of a n aerosol leads to both edge poloidal velocity shear and edge electric field shear. . I n t r o d u c t i o nIt has been well documented that the fusion performance of discharges in the Tokamak Fusion Test Reactor (TFTR) was strongly dependent on the physical and chemical condition of the graphite surface forming its limiter [1,2]. In particular, the highperformance supershot mode of operation was attainable at high currents (>2.0 MA) only when the graphite inner wall had previously been "scoured" by repeated discharges heated by high-power neutral beam injection (NBI) in order to render the limiter surface free of loosely-bound carbon and loosely-adsorbed hydrogenic material. At the end of a series of such pre-conditioning discharges, plasma fueling from the limiter typically reached a minimum.Moreover, only when this low-recycling condition had been attained did high levels of fusion performance become accessible.It has also been well documented that dramatic improvements in supershot fusion performance were attainable by the deposition of elemental lithium (Li) onto the limiter surface once it had been brought into the low-recycling condition. This deposition was carried out in earlier experiments by the injection and ablation of a few small (3 mg each) Li pellets [3,4,5,6]. In order to improve plasma performance during NBI, Li pellets were typically injected into the Ohmic phase of discharges and the ablated Li was allowed to 3 condense out of the plasma column and onto the limiter surface before the application of auxiliary heating. While the use of Li pellets did improve plasma performance, the technique was, nonetheless, highly perturbing. In order to reduce the perturbation to the plasma, brief but successful experiments with a Li effusion oven were also carried out on TFTR and are described elsewhere [7,8].While the use of an oven did result in an increase in the amount of Li deposited onto the inner wall as compared to pellet injection, deposition could only take place between discharges and not during the discharge of interest.In this work, an alternate wall-conditioning technique is described in which Li was injected into the scrape-off layer (SOL), during pl...

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Enhancement of Tokamak Fusion Test Reactor performance by lithium conditioning

Cited by 177 publications

References 10 publications

Technological aspects of lithium capillary-pore systems application in tokamak device

Technological aspects of lithium capillary-pore systems application in tokamak device

Plasma–lithium interaction in the CDX-U spherical torus

Observations concerning the injection of a lithium aerosol into the edge of TFTR discharges

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