Integration of Large-Scale Simulations and Numerical Modelling Tools in Close Link with the LHD Experiment

Yokoyama, M.; Seki, R.; Suzuki, C.; Emoto, M.; Ida, K.; Osakabe, M.; Murakami, S.; Suzuki, Yasuhiro; Satake, S.; Nunami, M.; Fukuyama, A.; Yamada, H.

doi:10.1585/pfr.9.3402017

Cited by 4 publications

(6 citation statements)

References 17 publications

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“…Here, a is the minor radius. In the experiments, we can estimate the total ion heat diffusivities by the power balance analysis using TASK3D-a code [15], as shown in Fig. 4.…”

Section: Ion Temperature In Hydrogen-and Helium-dominated Plasmas In ...mentioning

confidence: 99%

“…Here, a is the minor radius. In the experiments, we can estimate the total ion heat diffusivities by the power balance analysis using TASK3D-a code [15], as shown in figure 4. In the helium-dominated case, the obtained diffusivity normalized by the gyro-Bohm factor of the hydrogen defined as a r º ( )…”

Section: Ion Temperature In Hydrogen-and Heliumdominated Plasmas In L...mentioning

confidence: 99%

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Microinstabilities in hydrogen- and helium-dominated multi-ion-species plasmas in LHD

Nunami¹,

Nakata²,

Sugama³

et al. 2017

Plasma Phys. Control. Fusion

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The ion scale microinstabilities in the Large Helical Device (LHD) are investigated by the gyrokinetic simulations for the multi-ion-species plasmas including hydrogen, helium, and impurity ions. The observations in the LHD experiments show that the ion temperature increases with the decreases of the ratio of hydrogen density to helium density. It is found from the linear gyrokinetic simulations with the multiion-species and real-mass kinetic electrons in the LHD discharges that the growth rates of the ion scale microinstabilities are reduced for the helium-dominated multi-species plasma compared with the hydrogen-dominated one. In addition to the differences of the conditions including the temperature, the density profiles, and the temperature ratio between both plasmas, due to the dependence on the mass number and the electric charge of the mixed ion species, the mixing length estimates obtained from the linear simulations predicts smaller ion thermal diffusivity for the helium-dominated plasma than the hydrogen-dominated one in the hydrogen gyro-Bohm unit, which is consistent with the experimental results.

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“…Here, a is the minor radius. In the experiments, we can estimate the total ion heat diffusivities by the power balance analysis using TASK3D-a code [15], as shown in Fig. 4.…”

Section: Ion Temperature In Hydrogen-and Helium-dominated Plasmas In ...mentioning

confidence: 99%

Section: Ion Temperature In Hydrogen-and Heliumdominated Plasmas In L...mentioning

confidence: 99%

Microinstabilities in hydrogen- and helium-dominated multi-ion-species plasmas in LHD

Nunami¹,

Nakata²,

Sugama³

et al. 2017

Plasma Phys. Control. Fusion

Self Cite

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Section: Stable Sustainment Of a Plasma Having Electron Internal Tranmentioning

confidence: 99%

“…Radial distributions of electron thermal diffusivity coefficients in the discharges with and without e-ITB are evaluated using a transport coefficient evaluation tool based on the power balance, TR-snap [21], built in the integrated modeling code for three-dimensional configuration (TASK3D) [22], and are plotted in figure 5. Significant decrease in the thermal diffusivity coefficient at the plasma core region inside ρ∼0.2 can be recognized, though fluctuations of the coefficients are large.…”

Section: Stable Sustainment Of a Plasma Having E-itb By Echmentioning

confidence: 99%

Stable sustainment of plasmas with electron internal transport barrier by ECH in the LHD

Yoshimura

Kasahara

Tokitani

et al. 2017

Plasma Phys. Control. Fusion

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The long pulse experiments in the LHD has made progress in sustainment of improved confinement states. It was found that steady-state sustainment of the plasmas with improved confinement at the core region, that is, electron internal transport barrier (e-ITB), was achieved with no significant difficulty. Sustainment of a plasma having e-ITB with the line average electron density n e_ave of 1.1×10 19 m −3 and the central electron temperature T e0 of ~3.5 keV for longer than 5 min only with 340 kW ECH power was successfully demonstrated.

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“…TASK3D-a, in brief, consists of modules for temperature/density profile fittings, VMEC [5] equilibrium specification, NBI deposition calculations [6] and steadystate/dynamic energy transport calculations, so that they are sequentially executed in an automated manner [7]. Analyses for multiple-timings in multiple discharges form the analysis database.…”

mentioning

confidence: 99%

A Statistical Approach for Predicting Thermal Diffusivity Profiles in Fusion Plasmas as a Transport Model

Yokoyama

2014

Plasma and Fusion Research

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A statistical approach is proposed to predict thermal diffusivity profiles as a transport "model" in fusion plasmas. It can provide regression expressions for the ion and electron heat diffusivities (χ i and χ e), separately, to construct their radial profiles. An approach that this letter is proposing outstrips the conventional scaling laws for the global confinement time (τ E) since it also deals with profiles (temperature, density, heating depositions etc.). This approach has become possible with the analysis database accumulated by the extensive application of the integrated transport analysis suite to experiment data. In this letter, TASK3D-a [M. Yokoyama et al., Plasma Fusion Res. 9, 3402017 (2014)] analysis database for high-ion-temperature (high-T i) plasmas [H. Takahashi et al., Nucl. Fusion 53, 073034 (2013)] in the LHD (Large Helical Device) [O. Kaneko et al., Nucl. Fusion 53, 104015 (2013)] is used as an example to describe an approach.

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Integration of Large-Scale Simulations and Numerical Modelling Tools in Close Link with the LHD Experiment

Cited by 4 publications

References 17 publications

Microinstabilities in hydrogen- and helium-dominated multi-ion-species plasmas in LHD

Microinstabilities in hydrogen- and helium-dominated multi-ion-species plasmas in LHD

Stable sustainment of plasmas with electron internal transport barrier by ECH in the LHD

A Statistical Approach for Predicting Thermal Diffusivity Profiles in Fusion Plasmas as a Transport Model

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