First Wall Components for the TCV Tokamak

Chavan, R.; Pitts, R.A.; Hofmann, F.; Hollenstein, Ch.; Moret, J.-M.; Rage, Ravitheja; Tonetti, G.

doi:10.1016/b978-0-444-89995-8.50036-9

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…However, one important practical observation is that no harm to the LFS first-wall components was detected in these configurations even up to 1.4-MW heating. The LFS graphite tiles were not explicitly designed for high-power handling [19] and yet survived several hundred high-power pulses -with an outer strike point placed on the LFS wall -entirely unscathed. It should be added that the vast majority of these shots were performed in the absence of the divertor baffles [20] that have now become a periodically recurrent feature of TCV.…”

Section: The Development Of Diverted Negative-triangularity Plasmas I...mentioning

confidence: 99%

Enhanced confinement in diverted negative-triangularity L-mode plasmas in TCV

Coda¹,

Merle²,

Sauter³

et al. 2021

Plasma Phys. Control. Fusion

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The favourable conﬁnement properties of negative-triangularity (NT) tokamak conﬁgurations were discovered in the TCV tokamak in the late 1990’s and were documented over the two following decades, through investigations of predominantly electron-heated plasmas in limited topologies. The most recent experimental campaign in TCV has marked a leap forward, characterized by the development of a variety of diverted NT shapes that are robustly stable with basic Ohmic heating. The application of auxiliary heating, directed now at both electrons and ions (using electron-cyclotron resonance heating as well as neutral-beam injection), has enabled the achievement of record performances for L-mode plasmas, with normalized β values reaching 2.8 transiently (as well as 2 in steady state, but reverting to a limited conﬁguration) and with comparable ion and electron temperatures. The systematic conﬁnement enhancement with NT is conﬁrmed in these experiments. The L-mode existence space is broader than at positive triangularity, with only sporadic transitions to Hmode observed up to 1.4-MW heating power regardless of the magnetic-ﬁeld-gradient direction relative to the X-point. These experiments are planned to be continued with even higher power following a heating-source upgrade.

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Section: The Development Of Diverted Negative-triangularity Plasmas I...mentioning

confidence: 99%

Enhanced confinement in diverted negative-triangularity L-mode plasmas in TCV

Coda¹,

Merle²,

Sauter³

et al. 2021

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

show abstract

“…During the first two years of TCV operation, graphite protection consisted of asymmetrically chamfered tiles for the central column, a set of tiles for the vessel floor, a toroidal belt limiter below the outside midplane and elsewhere individual tiles installed only for the protection of in-vessel poloidal magnetic field probes [9]. In 1993, new tile sets, optimized for diverted discharges (e.g.…”

Section: Tcv Equilibria and First Wall Protectionmentioning

confidence: 99%

The design of central column protection tiles for the TCV tokamak

1999

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The large variety of plasma shapes produced in the TCV tokamak places unique demands on the plasma facing surfaces. In particular, the central column graphite armour tiles are solicited during the creation of all TCV plasmas and function as power handling surfaces for both limited and diverted discharges. The higher power flux densities accompanying the addition of electron cyclotron heating systems have necessitated a new, optimized, design for these tiles. The optimization process and the subsequent new tile design are described. A basic 'two point' model of the scrape-off layer plasma in conjunction with TCV equilibrium reconstructions and a simplified representation of the local magnetic field line geometry are used to impose simulated power flux densities onto a parametric toroidal tile contour. The thermo-mechanical response of the tile is then investigated via full 3-D finite element simulations accounting for the non-linear temperature dependence of the graphite thermal diffusivity and radiation from the tile surface. The final design choice is a compromise between the requirements for adequate power handling for a range of magnetic configurations, the need to protect against tile edge misalignment in the presence of grazing field line angles of incidence and the space restrictions imposed by vacuum vessel design.

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“…The employment of MIC for inductive sensors has been well established in magnetic confinement machines -DIII-D [3], TCV [4], JET [5], KSTAR [6], and even ITER [7]; compatibility with high temperature and neutron and γ fluxes makes MIC a good candidate for both signal transmission and inductive sensors in fusion machines with high nuclear radiation yields. However, the usage of MIC for sensors comes with drawbacks.…”

Section: Introductionmentioning

confidence: 99%

Mineral insulated cable assessment for inductive magnetic diagnostic sensors of a hot-wall tokamak

et al. 2019

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ITER and DEMO relevant plasma exhaust physics, including operation with liquid metal divertor. Inductive magnetic diagnostics based on conductive loops of different geometry and orientation are crucial for magnetic confinement fusion devices. Due to the high temperatures of the vacuum vessel upon which they will be operated, a suitable cable insulation needs to be chosen carefully. Mineral-insulated cables (MIC) have proven to be compatible with high baking temperatures. However, the steel sheath of MIC attenuates the response of the sensor at higher frequencies which could affect real-time plasma control feedback and magnetic equilibrium reconstruction. In this work, characterization and testing of multiple MgO MIC of different diameters was conducted. A variety of electrical property measurements, such as frequency attenuation, resistance and capacitance, for each cable is presented, both at low and high temperatures up to 300 • C. Cutoff frequencies from 65 kHz to 335 kHz were identified and attributed to the shielding in a flux loop configuration. Using an external RLC circuit, the frequency response of MIC coils is compared to an electrical model for shielded coils, yielding an useful calibrated model for future probe prototypes with different geometries in the frequency range of interest. K: Detector design and construction technologies and materials; Plasma diagnosticsprobes; Special cables 1Corresponding author.

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First Wall Components for the TCV Tokamak

Cited by 3 publications

References 2 publications

Enhanced confinement in diverted negative-triangularity L-mode plasmas in TCV

Enhanced confinement in diverted negative-triangularity L-mode plasmas in TCV

The design of central column protection tiles for the TCV tokamak

Mineral insulated cable assessment for inductive magnetic diagnostic sensors of a hot-wall tokamak

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