Multi-field/multi-scale turbulence response to electron cyclotron heating of DIII-D ohmic plasmas

Wang, G.; Peebles, W. A.; Rhodes, T. L.; DeBoo, J. C.; Staebler, G. M.; Hillesheim, J. C.; Yan, Z.; McKee, G. R.; Petty, C. C.; Solomon, W. M.; Burrell, K.H.; Doyle, E. J.; Leonard, A.W.; Schmitz, L.; Vanzeeland, M.; White, Anne; Zeng, L.

doi:10.1063/1.3610552

Cited by 8 publications

(5 citation statements)

References 34 publications

(40 reference statements)

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“…Extensive validation has been performed on the quasilinear growth rates and frequencies [54,58], quasilinear cross-phases [59] and nonlinear fluxes [60,61]. The switch settings used for the predictive modelling with QuaLiKiz are listed in table 6 in appendix C.…”

Section: (I) Tglfmentioning

confidence: 99%

Validation of D–T fusion power prediction capability against 2021 JET D–T experiments

Kim,

Auriemma,

Ferreira

et al. 2023

Nucl. Fusion

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JET experiments using the fuel mixture envisaged for fusion power plants, deuterium and tritium (D–T), provide a unique opportunity to validate existing D–T fusion power prediction capabilities in support of future device design and operation preparation. The 2021 JET D–T experimental campaign has achieved D–T fusion powers sustained over 5 s in ITER-relevant conditions i.e. operation with the baseline or hybrid scenario in the full metallic wall. In preparation of the 2021 JET D–T experimental campaign, extensive D–T predictive modelling was carried out with several assumptions based on D discharges. To improve the validity of ITER D–T predictive modelling in the future, it is important to use the input data measured from 2021 JET D–T discharges in the present core predictive modelling, and to specify the accuracy of the D–T fusion power prediction in comparison with the experiments. This paper reports on the validation of the core integrated modelling with TRANSP, JINTRAC, and ETS coupled with a quasilinear turbulent transport model (Trapped Gyro Landau Fluid or QualLiKiz) against the measured data in 2021 JET D–T discharges. Detailed simulation settings and the heating and transport models used are described. The D–T fusion power calculated with the interpretive TRANSP runs for 38 D–T discharges (12 baseline and 26 hybrid discharges) reproduced the measured values within 20 % . This indicates the additional uncertainties, that could result from the measurement error bars in kinetic profiles, impurity contents and neutron rates, and also from the beam-thermal fusion reaction modelling, are less than 20 % in total. The good statistical agreement confirms that we have the capability to accurately calculate the D–T fusion power if correct kinetic profiles are predicted, and indicates that any larger deviation of the D–T fusion power prediction from the measured fusion power could be attributed to the deviation of the predicted kinetic profiles from the measured kinetic profiles in these plasma scenarios. Without any posterior adjustment of the simulation settings, the ratio of predicted D–T fusion power to the measured fusion power was found as 65%–96% for the D–T baseline and 81%–97% for D–T hybrid discharge. Possible reasons for the lower D–T prediction are discussed and future works to improve the fusion power prediction capability are suggested. The D–T predictive modelling results have also been compared to the predictive modelling of the counterpart D discharges, where the key engineering parameters are similar. Features in the predicted kinetic profiles of D–T discharges such as underprediction of ne are also found in the prediction results of the counterpart D discharges, and it leads to similar levels of the normalized neutron rate prediction between the modelling results of D–T and the counterpart D discharges. This implies that the credibility of D–T fusion power prediction could be a priori estimated by the prediction quality of the preparatory D discharges, which will be attempted before actual D–T experiments.

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Section: (I) Tglfmentioning

confidence: 99%

Validation of D–T fusion power prediction capability against 2021 JET D–T experiments

Kim,

Auriemma,

Ferreira

et al. 2023

Nucl. Fusion

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“…Investigation of the role of electron temperature gradient modes in electron heat transport in TCV plasmas significant electron heat transport [3]. Indeed, from the experimental side, a correlation between the increase of the electron heat flux q e and the increase of high-k density fluctuations has been reported in [4][5][6][7][8]. Modelling plasmas featuring ETGs by means of gyrokinetic (GK) [9] codes can give an insight on the impact that they have on the turbulent transport.…”

Section: Nuclear Fusionmentioning

confidence: 99%

Investigation of the role of electron temperature gradient modes in electron heat transport in TCV plasmas

et al. 2019

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Electron-scale micro-turbulence driven by the electron temperature gradient (ETG) instability have recently been shown to impact the electron heat transport in tokamaks. Given the relevance of these mechanisms for ITER scenarios, a new study has been carried out on the TCV tokamak at the Swiss Plasma Center, which is equipped with both ECH and NBI heating, allowing to investigate the relevance of ETG transport. Dedicated L-mode TCV discharges have been performed and the experimental measurements have been compared with gyrokinetic simulations. The results indicate that ETGs should contribute to electron heat transport from midradius to the edge when NBI and ECH are simultaneously applied, while the cases with pure ECH are dominated by ion-scale turbulence at mid-radius and show signs of possible ETG contribution only at outer radii.

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“…The study of the transport and plasma turbulence during ECRH directly implicates ITER [7], where ECRH is one of the vital heating systems. The electron thermal transport diffusivities and plasma turbulence have been studied in DIII-D for different cases, including ECRH in ohmic plasmas [8], low-confinement mode (L-mode) plasmas [9], and high-confinement mode (H-mode) plasmas [10]. Experimental results from DIII-D found that long-wavelength electron temperature fluctuations play an important role in determining electron thermal transport in L-mode plasmas [9] and H-mode plasmas [10].…”

Section: Introductionmentioning

confidence: 99%

“…Experimental results from DIII-D found that long-wavelength electron temperature fluctuations play an important role in determining electron thermal transport in L-mode plasmas [9] and H-mode plasmas [10]. Additionally, it was found that the high-k density fluctuation level can also have a significant effect on the electron thermal transport [8]. To determine the connection between plasma turbulence and heat transport, more detailed experimental work is required.…”

Section: Introductionmentioning

confidence: 99%

Observation of the electron thermal transport and temperature fluctuations for electron cyclotron resonance heated plasmas on J-TEXT

Yang¹,

Zhang²,

Ren³

et al. 2021

Nucl. Fusion

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First dedicated experiments have been carried out on the J-TEXT tokamak for investigating the electron thermal transport and plasma fluctuations before and during electron cyclotron resonance heating (ECRH). The electron thermal diffusivities are calculated using the diffusive space-time evolution characteristic of the electron temperature perturbations produced by internal sawtooth collapse. It is found that the electron thermal diffusivity significantly increases as ECRH is turned on. The temperature fluctuations in the ECRH-assisted ohmic plasmas measured by the correlation electron cyclotron emission (CECE) diagnostic have a larger amplitude and broader bandwidth than that of pure ohmic plasmas. However, there is a slight change in the density fluctuations. The electron thermal diffusivities and the bandwidth of the electron temperature fluctuations decrease simultaneously as density increases in ohmic plasmas. However, the same trend is not found for ECRH-assisted ohmic plasmas with fixed ECRH power. The electron thermal diffusivities increase almost linearly with the ECRH power for the same discharge parameters, while the temperature fluctuations become broader at the same time. Linear stability analysis using the gyrokinetic electromagnetic numerical experiment code indicates that there is a turbulence transition from the mixed mode of ion temperature gradient mode and trapped electron mode (TEM) to the pure (broader) TEM when changing from pure ohmic to ECRH-assisted ohmic plasmas. It is consistent with the temperature fluctuations measured by CECE, which is sensitive to the long-wavelength modes. All these results suggest that the long-wavelength temperature fluctuations play an important role in electron thermal transport. In ECRH-assisted ohmic plasmas, electron thermal transport may become dominated by ETGs when TEMs are suppressed at high density.

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Multi-field/multi-scale turbulence response to electron cyclotron heating of DIII-D ohmic plasmas

Cited by 8 publications

References 34 publications

Validation of D–T fusion power prediction capability against 2021 JET D–T experiments

Validation of D–T fusion power prediction capability against 2021 JET D–T experiments

Investigation of the role of electron temperature gradient modes in electron heat transport in TCV plasmas

Observation of the electron thermal transport and temperature fluctuations for electron cyclotron resonance heated plasmas on J-TEXT

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