Overview of TJ-II experiments

Sánchez, J.; Acedo, M.; Alegre, D.; Alonso, A.; Alonso, Javier; Álvarez, Pedro; Arévalo, Juan Miguel Insúa; Ascasíbar, E.; Baciero, A.; Baião, D.; Barrera, L.; Blanco, E.; Botija, J.; Bustos, A.; Cal, E. de la; Calvo, I.; Cappa, Á.; Carralero, D.; Carrasco, R. C.; Carreras, B. A.; Castejón, F.; Castro, R.; Catalán, Gustau; Chmyga, A. A.; Chamorro, M.; Eliseev, L.G.; Esteban, Luis; Estrada, T.; Ferreira, J. A.; Fontdecaba, J. M.; Garcia, L.; García-Gómez, R.; García-Regaña, J. M.; García-Sánchez, Pablo; Gomez‐Iglesias, Alvaro; González, Sergio A.; Guasp, J.; Happel, T.; Hernanz, J.; Herranz, J.; Hidalgo, C.; Jiménez, Javier; Jiménez-Denche, A.; Jiménez‐Gómez, R.; Kirpitchev, I.; Komarov, A. D.; Kozachok, A. S.; Krupnik, L. I.; Lapayese, F.; Liniers, M.; López‐Bruna, D.; Löpez‐Fraguas, A.; López-Razola, J.; Madeira, Teresa; Martín-Díaz, F.; Martín-Hernández, F.; Martín-Rojo, A.B.; Martínez-Fernández, J.; McCarthy, K. J.; Medina, F.; Medrano, M.; Melón, L.; Melnikov, A. V.; Méndez, P.; Milligen, B. Ph. van; Mirones, E.; Molinero, A.; Navarro, Moses; Nedzelskiy, I. S.; Ochando, M. A.; Olivares, Javier; Oyarzábal, E.; Pablos, J.L. de; Pacios, Luis F.; Pastor, I.; Pedrosa, M. A.; Peña, A. de la; Pereira, A.; Petrov, Alexander; Petrov, S.; Portas, A.; Rattá, G.A.; Reynolds, J. M.; Rincón, E.; Ríos, Luis; Rodríguez, C. O.; Rojo, B.; Romero, Jesús; Ros, Agustin J.; Sánchez, M.; Sánchez, E.; Sánchez-Burillo, G.; Sánchez-Sarabia, E.; Sarksian, K. A.; Sebastián, J.A.; Silva, Carlos; Solano, E.R.; Soleto, A.; Tabarés, F.L.; Tafalla, D.; Tera, J.; Tolkachev, A.; Vega, J.; Velasco, G.; Velasco, J. L.; Weber, Markus; Wolfers, G.; Zurro, B.

doi:10.1088/0029-5515/51/9/094022

Cited by 24 publications

(13 citation statements)

References 55 publications

(69 reference statements)

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“…Note, for example, the change of trend in the diamagnetic energy at the transition in figure 7(b). One systematic effect of the L-H transition in TJ-II plasmas is the widening and flattening of the emissivity profiles and a corresponding increment of the radiated power near the edge [37][38][39]. This is partly a consequence of the broadening of the density profile but also of the cooling of the edge.…”

Section: Relation With Transport Barriersmentioning

confidence: 99%

Relationship between MHD events, magnetic resonances and transport barriers in TJ-II plasmas

López‐Bruna¹,

Ochando²,

Löpez‐Fraguas³

et al. 2013

Nucl. Fusion

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In the TJ-II stellarator, a medium-sized heliac device that operates at high rotational transform and low magnetic shear, a close relationship is identified between abrupt changes in transport (in the form of radial fluxes, edge or internal transport barriers), broadband magnetohydrodynamic (MHD) events and the location of magnetic resonances. The observations are based on the local behaviour of plasma radiation. Phenomena that appear like sawteeth and crashes in tokamaks are found in practically all kinds of plasmas and show intensities and repetition rates that depend on plasma parameters. The magnetic resonances are suggested as important transport regulators in normal operation.

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Section: Relation With Transport Barriersmentioning

confidence: 99%

Relationship between MHD events, magnetic resonances and transport barriers in TJ-II plasmas

López‐Bruna¹,

Ochando²,

Löpez‐Fraguas³

et al. 2013

Nucl. Fusion

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“…In TFTR, long energy confinement time and high D-T fusion power production were obtained by injection of Li pellets into plasmas [7]. Li coatings have also significantly improved the plasma performances and L-mode to H-mode power threshold by 20-30% in TJ-II [8] and in NSTX [9]. Edge Local Mode (ELM)-free periods of enhanced pedestals were obtained with Li conditioning in NSTX [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

First results of the use of a continuously flowing lithium limiter in high performance discharges in the EAST device

Zuo

Ren

et al. 2016

Nucl. Fusion

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As an alternative choice of solid plasma facing components (PFCs), flowing liquid lithium can serve as a limiter or divertor PFC and offers a self-healing surface with acceptable heat removal and good impurity control. Such a system could improve plasma performance, and therefore be attractive for future fusion devices. Recently, a continuously flowing liquid lithium (FLiLi) limiter has been successfully designed and tested in the EAST superconducting tokamak. A circulating lithium layer with a thickness of <0.1 mm and a flow rate ~2 cm3 s−1 was achieved. A novel in-vessel electro-magnetic pump, working with the toroidal magnetic field of the EAST device, was reliable to control the lithium flow speed. The flowing liquid limiter was found to be fully compatible with various plasma scenarios, including high confinement mode plasmas heated by lower hybrid waves or by neutral beam injection. It was also found that the controllable lithium emission from the limiter was beneficial for the reduction of recycling and impurities, for the reduction of divertor heat flux, and in certain cases, for the improvement of plasma stored energy, which bodes well application for the use of flowing liquid lithium PFCs in future fusion devices.

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“…Results from NSTX [8], EAST, smaller limiter tokamaks [9,10] and stellarators [11] have demonstrated the positive benefits of lithium wall conditioning techniques. These include increased energy confinement time [11,12], reduced H-mode power threshold [13,14], reduced divertor recycling [15] and the elimination of edge localized modes (ELMs) [16]. NSTX now routinely uses lithium as a wall conditioning technique instead of boronization [17].…”

Section: Introductionmentioning

confidence: 99%

The effects of increasing lithium deposition on the power exhaust channel in NSTX

et al. 2014

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Previous measurements on the National Spherical Torus Experiment (NSTX) demonstrated peak, perpendicular heat fluxes, qdep,pk⩽15 MW m−2 with an inter-edge localized mode integral heat flux width, during high performance, high power operation (plasma current, Ip = 1.2 MA and injected neutral beam power, PNBI = 6 MW) when magnetically mapped to the outer midplane. Analysis indicates that scales approximately as . The extrapolation of the divertor heat flux and λq for NSTX-U are predicted to be upwards of 24 MW m−2 and 3 mm, respectively assuming a high magnetic flux expansion, fexp ∼ 30, PNBI = 10 MW, balanced double null operation and boronized wall conditioning. While the divertor heat flux has been shown to be mitigated through increased magnetic flux expansion, impurity gas puffing, and innovative divertor configurations on NSTX, the application of evaporative lithium coatings in NSTX has shown reduced peak heat flux from 5 to 2 MW m−2 during similar operation with 150 and 300 mg of pre-discharge lithium evaporation respectively. Measurement of divertor surface temperatures in lithiated NSTX discharges is achieved with a unique dual-band IR thermography system to mitigate the variable surface emissivity introduced by evaporative lithium coatings. This results in a relative increase in divertor radiation as measured by divertor bolometry. While the measured divertor heat flux is reduced with strong lithium evaporation, λq contracts to 3–6 mm at low Ip but remains nearly constant as Ip is increased to 1.2 MA yielding λq's comparable to no lithium discharges at high Ip.

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Overview of TJ-II experiments

Cited by 24 publications

References 55 publications

Relationship between MHD events, magnetic resonances and transport barriers in TJ-II plasmas

Relationship between MHD events, magnetic resonances and transport barriers in TJ-II plasmas

First results of the use of a continuously flowing lithium limiter in high performance discharges in the EAST device

The effects of increasing lithium deposition on the power exhaust channel in NSTX

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