Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation

Bucalossi, J.

doi:10.1088/1741-4326/ac2525

Cited by 74 publications

(42 citation statements)

References 51 publications

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“…Note that W was not accumulated in the core plasma over 1000 s. This behavior is similar to that observed in WEST plasmas heated by RF powers, which is attributed to the low torque driven by the RF waves ( 24 ). Note that the increase in central W accumulation is due to the neoclassical convection increasing with toroidal rotation.…”

Section: Resultssupporting

confidence: 77%

Realization of thousand-second improved confinement plasma with Super I-mode in Tokamak EAST

et al. 2023

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Mastering nuclear fusion, which is an abundant, safe, and environmentally competitive energy, is a great challenge for humanity. Tokamak represents one of the most promising paths toward controlled fusion. Obtaining a high-performance, steady-state, and long-pulse plasma regime remains a critical issue. Recently, a big breakthrough in steady-state operation was made on the Experimental Advanced Superconducting Tokamak (EAST). A steady-state plasma with a world-record pulse length of 1056 s was obtained, where the density and the divertor peak heat flux were well controlled, with no core impurity accumulation, and a new high-confinement and self-organizing regime (Super I-mode = I-mode + e-ITB) was discovered and demonstrated. These achievements contribute to the integration of fusion plasma technology and physics, which is essential to operate next-step devices.

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Section: Resultssupporting

confidence: 77%

Realization of thousand-second improved confinement plasma with Super I-mode in Tokamak EAST

et al. 2023

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“…This is illustrated in figure 7: during a slow ramp of density, when the core radiation exceeds 0.15MW/m 3 , Te(0) decreases from 2.4keV to 1.7keV in 200ms and the MHD activity starts at this point. Energy confinement is first evaluated with respect of the L-mode scaling law ITER-L-96P [9]. Interestingly, this scaling law was derived mostly for plasmas having an aspect ratio A ~3 and found almost no dependence with A.…”

Section: Electron Heating and Energy Confinementmentioning

confidence: 99%

Developing high performance RF heating scenarios on the WEST tokamak

Goniche

Ostuni²,

Bourdelle³

et al. 2022

Nucl. Fusion

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High power experiments, up to 9.2 MW with LHCD and ICRH, have been carried out in the full tungsten tokamak WEST. Quasi non inductive discharges have been achieved allowing to extend the plasma duration to 53s with stationary conditions in particular with respect to tungsten contamination. Transitions in H mode are obtained lasting up to 4s with weak energy increment at the power crossing the separatrix is close to the threshold. Hot L mode plasmas (Te(0)>3keV) with a confinement time following the ITER L96 scaling are routinely obtained. The weak aspect ratio dependence of this scaling law is confirmed. Tungsten accumulation is generally not an operational issue on WEST. Difficulty of burning through tungsten can prevent from accessing to a hot core plasma in the ramp-up phase or can lead to rapid collapse of the central temperature when radiation is enhanced by a slight decrease of the temperature. Apart few pulses post-boronization, the plasma radiation is rather high (Prad/Ptot~50%) and is dominated by tungsten. This fraction does not vary as the RF power is ramped up and is quite similar in ICRH and/or LHCD heated plasmas. An estimate of the contribution of the RF antennas to the plasma contamination in tungsten is given

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“…While boronization may not be desirable for a fusion pilot plant due to the T retention of the B films, it remains a valuable tool to expand the operational windows of present day tokamaks and stellarators. Boronization has been especially important to achieve high density regimes in WEST [9] and to suppress the sputtering of high-Z particles in other metal-walled tokamaks [10,11].…”

Section: Introductionmentioning

confidence: 99%

Initial results from boron powder injection experiments in WEST lower single null L-mode plasmas

Bodner¹,

Gallo²,

Diallo³

et al. 2022

Nucl. Fusion

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Using a recently installed impurity powder dropper (IPD), boron powder (< 150 μm) was injected into lower single null (LSN) L-mode discharges in WEST. IPDs possibly enable real-time wall conditioning of the plasma-facing components and may help to facilitate H-mode access in the full-tungsten environment of WEST. The discharges in this experiment featured Ip = 0.5 MA, BT = 3.7 T, q95 = 4.3, tpulse = 12–30 s, ne,0 ~ 4×1019 m-2, and PLHCD ~ 4.5 MW. Estimates of the deuterium and impurity particle fluxes, derived from a combination of visible spectroscopy measurements and their corresponding S/XB coefficients, showed decreases of ~ 50% in O+, N+, and C+ populations during powder injection and a moderate reduction of these low-Z impurities (~ 50%) and W (~ 10%) in the discharges that followed powder injection. Along with the improved wall conditions, WEST discharges with B powder injection observed improved confinement, as the stored energy WMHD, neutron rate, and electron temperature Te increased significantly (10–25% for WMHD and 60–200% for the neutron rate) at constant input power. These increases in confinement scale up with the powder drop rate and are likely due to the suppression of ion temperature gradient (ITG) turbulence from changes in Zeff and/or modifications to the electron density profile.

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Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation

Cited by 74 publications

References 51 publications

Realization of thousand-second improved confinement plasma with Super I-mode in Tokamak EAST

Realization of thousand-second improved confinement plasma with Super I-mode in Tokamak EAST

Developing high performance RF heating scenarios on the WEST tokamak

Initial results from boron powder injection experiments in WEST lower single null L-mode plasmas

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