Sawtooth control with modulated ICRH in JET-ILW H-mode plasmas

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For more than a decade, an unprecedented predict-first activity has been carried in order to predict the fusion power and provide guidance to the second Deuterium–Tritium (D–T) campaign performed at JET in 2021 (DTE2). Such an activity has provided a framework for a broad model validation and development towards the D–T operation. It is shown that it is necessary to go beyond projections using scaling laws in order to obtain detailed physics based predictions. Furthermore, mixing different modelling complexity and promoting an extended interplay between modelling and experiment are essential towards reliable predictions of D–T plasmas. The fusion power obtained in this predict-first activity is in broad agreement with the one finally measured in DTE2. Implications for the prediction of fusion power in future devices, such as ITER, are discussed.

Section: Icrh Modellingmentioning

confidence: 99%

Modelling performed for predictions of fusion power in JET DTE2: overview and lessons learnt

Garcia,

Casson,

Frassinetti

et al. 2023

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“…It has a dramatic effect on bulk plasma confinement, resulting in a drop in central density and temperature. They also interact with fast ions, where the sawtooth period is seen to be modified in the presence of fast ions [3][4][5] and, conversely, where the fast ion transport deviates farther from neoclassical theory as shown theoretically and experimentally [6][7][8][9].…”

Section: Introductionmentioning

confidence: 90%

Modelling of sawtooth-induced fast ion transport in positive and negative triangularity in TCV

Vallar¹,

Podestà²,

Baquero-Ruiz³

et al. 2021

Internal kinks are a common magneto hydro-dynamic (MHD) instability observed in tokamak operation when the q profile in the plasma core is close to unity. This MHD instability impacts both the transport of the bulk plasma (current, particle and energy transport) and minority species, such as fast ions. In TCV (R 0 /a = 0.88 m/0.25 m) the fast ion population is generated in the plasma by neutral beam tangential injection of energies up to 28 keV. TCV features 16 active shaping coils permitting a great flexibility in plasma shape, including negative triangularity (δ) configurations that show surprisingly high confinement. This study focuses on the transport of fast ions induced by sawteeth, by comparing two triangularity cases and simulation results with experimental data. Comparison of two equilibria with opposite δ shows that the fast ion drifts are larger for δ < 0. Furthermore, the sawtooth-induced transport in this case is larger than δ > 0 in similar conditions. Comparison with experimental data confirms the dominance of the modification of thermal kinetic profiles following the sawtooth crash in explaining drops in the neutron rates and FIDA signals. Additional fast ion diffusion, however, improves the interpretation of the experimental data. For δ < 0, the amplitude of the perturbation better representing the experimental data is larger. Finaly, an exploratory study for 50 keV particles (soon available in TCV) shows that the situation does not worsen for such particles.

“…An ion cyclotron range of frequency (ICRF) system can provide power for several tasks [1], experimentally verified on present-day machines: heating and current drive, first wall conditioning [2], plasma start-up, removing of impurities from the core [3,4], controlling sawteeth [5] and current ramp down assist [6][7][8]. The system could be designed to have a high plugto-power efficiency.…”

Section: Introductionmentioning

confidence: 99%

Status of the WEST travelling wave array antenna design and results from the high power mock-up

Ragona¹,

Durodié²,

Messiaen³

et al. 2022

A mock-up of the WEST TWA antenna was designed in 2019, manufactured during 2020 and installed in the TITAN test facility in the beginning of 2021. The paper presents the current status of the WEST TWA antenna, its mock-up and a possible extrapolation to DEMO. The updated WEST TWA design has a reduced antenna length and features feeding and mechanical support from a single vessel port. The first results of the mock-up at low power, its diagnostic system and the prospects are explained. Extensions versus a TWA antenna for WEST, and a possible DEMO TWA system are briefly discussed.