Improved high-performance fully non-inductive discharge by optimizing the fast-ion confinement on EAST

Huang, J.; Qian, J.; Garofalo, A. M.; Gong, Xianzu; Wu, Cong-Feng; Chang, Jiafeng; Zhang, J.; Du, Haifeng; Wu, Muquan; Hao, Baolong; Yu, Luyang; Zhang, X.M.; Madsen, B.; Salewski, M.; Liang, Lizhen; Li, J.; Ding, Siye; Zhong, Guoqiang; Chen, J.L.; Zhu, Xiang; Zeng, Long; Li, Erzhong; Zhang, B.; Xu, Zhuang; Su, Jingzhi; Gao, Wei; Chen, Y.J.; Li, Y.Y.; Liu, H.; Lyu, Bo; Zang, Qing; Wan, Baonian

doi:10.1088/1741-4326/ab443a

Cited by 20 publications

(16 citation statements)

References 18 publications

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“…Other features such as a metal wall (tungsten divertor), low torque injection (T inj ∼ 1.0 Nm), electron dominated heating (T e > T i ), moderate bootstrap current fraction ( f bs ∼ 50%), broad current density profile with the central q(0) > 1.0 and good energy confinement have also been demonstrated in this scenario. Note that high-Z impurity accumulation in the plasma core was well controlled at a low level by using the on-axis ECH (P EC = 0.8 MW) from 2 s to 19 s and the fast ion losses were reduced through beam energy optimization [15]. Previous experiments in EAST have also successfully demonstrated that at higher density, the fast-ion contribution to the total plasma pressure was decreased due to reduced fast-ion slowing down time [15], which would achieve higher bootstrap fraction at the same β p level as fast ions do not contribute significantly to the bootstrap current.…”

Section: Development Of Long Pulse High Poloidal Beta Scenarios With ...mentioning

confidence: 99%

EAST steady-state long pulse H-mode with core-edge integration for CFETR

Gong¹,

Garofalo²,

Huang³

et al. 2022

Nucl. Fusion

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Recent EAST experiment has successfully demonstrated long pulse steady-state high plasma performance scenario and core-edge integration since the last IAEA in 2018. A discharge with a duration over 60s with βP ~2.0, βN ~1.6, H98y2~1.3 and internal transport barrier on electron temperature channel is obtained with multi-RF power heating and current drive. A higher βN (βN~1.8, βp~2.0, H98y2~1.3, ne/nGW~0.75) with a duration of 20s is achieved by using the modulated neutral beam and multi-RF power, where several normalized parameters are close or even higher than the phase III 1GW scenario of CFETR steady-state. High-Z impurity accumulation in the plasma core is well controlled in a low level by using the on-axis ECH. Modelling shows that the strong diffusion of TEM turbulence in the central region prevents tungsten impurity to accumulate. More recently, EAST has demonstrated compatible core-edge integration discharges in the high βp scenario: high confinement H98y2>1.2 with high βP~2.5/βN~2.0 and fbs~50% is sustained with reduced divertor heat flux at high density ne/nGW~0.7 and moderate q95~6.7. By combining active impurity seeding through radiative divertor feedback control and strike point splitting induced by resonant perturbation coil, the peak heat flux is reduced by 20-30% on the ITER-like tungsten divertor, here a mixture of 50% neon and 50% D2 is applied.

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Section: Development Of Long Pulse High Poloidal Beta Scenarios With ...mentioning

confidence: 99%

EAST steady-state long pulse H-mode with core-edge integration for CFETR

Gong¹,

Garofalo²,

Huang³

et al. 2022

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

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“…The experiments have been carried out with the conventional 10 s setting since the EAST NBI cannot sustain long-pulse operation at a high beam voltage (V beam > 60 kV). It should be stressed here that high density (〈n e 〉 = 4.0-5.0 × 10 19 m −3 ) was routinely used for those discharges using NBI to avoid strong shine-through loss [13]. In addition to the exploration of the high β P scenarios, extensive experiments of high β N scenario development have been carried out on EAST.…”

Section: Extension Of Steady-state Operational Regime With Dominant R...mentioning

confidence: 99%

Recent advances in EAST physics experiments in support of steady-state operation for ITER and CFETR

et al. 2019

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The recent EAST experimental progress since the last IAEA FEC in 2016 is presented. First demonstration of >100 seconds time scale long-pulse steady-state scenario with a good plasma performance (H98(y2) ~ 1.1) and a good control of impurity and heat exhaust with the tungsten divertor has been successfully achieved on EAST using the pure RF power heating and current drive. The extended operation regimes have been obtained (βP~2.5 & βN~1.9 of using RF&NB and βP~1.9 & βN~1.5). High bootstrap current fraction up to 47% was achieved with q95~6.0-7.0. The interaction effect between the ECH and two LHW systems has been investigated for enhanced current drive and improved confinement quality. ELM suppression using the n= 2 RMPs has been achieved at q95 (≈ 3.2-3.7) with standard type-I ELMy H-mode operational window in EAST. Reduction of the peak heat flux on the divertor was demonstrated using the active radiation feedback control. An increase in the total heating power and improvement of the plasma confinement are expected using a 0-D model prediction for higher bootstrap fraction. Towards long pulse, high bootstrap current fraction operation, a new lower ITER-like tungsten divertor with active watercooling will be installed, together with further increase and improvement of heating and current drive capability.

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“…The toroidal angles of the beam source for NBI1L, NBI1R, NBI2L, and NBI2R are 74.14 • , 79.41 • , −148.62 • , and −143.33 • (right-handed), respectively. The details of the NBI system can be found in reference [22]. In these discharges that show the similar tendency, the plasma is mainly heated by the two NBI systems with similar power configuration, i.e., the NBI power is stepped increased by the in-sequence injection of NBI1L, NBI1R, NBI2L and NBI2R sources.…”

Section: Resultsmentioning

confidence: 91%

Study on filament width of type-I ELM in EAST using VUV imaging system and simulation

Ming

Tang²,

Shi³

et al. 2022

Nucl. Fusion

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The poloidal width of the filaments induced by the Type-I edge localized mode has power dependence in EAST. The poloidal widths of the filaments observed by the high-speed vacuum ultraviolet (VUV) imaging system are proportional to the heating power and the ELM size. To understand this power dependence, the BOUT++ nonlinear simulations have been performed with the reconstructed equilibriums from the experimental measurements in this paper. The synthetic filament structures from BOUT++ nonlinear simulation match the experimental observations by the VUV imaging system. The BOUT++ nonlinear simulations also reproduce the power dependence of the filament widths and the ELM size. The filament width and the ELM size are inversely proportional to the toroidal mode number. The low-n mode has a broader radial and poloidal structure, which causes the larger filament width and ELM size. In the high input power case, the mode spectrum shifts to low-n, a result of increasing peeling drive. Besides, we found the β_p in a higher input power case leads to a broader pedestal, expanding the radial mode structure of the Peeling-Ballooning mode.

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Improved high-performance fully non-inductive discharge by optimizing the fast-ion confinement on EAST

Cited by 20 publications

References 18 publications

EAST steady-state long pulse H-mode with core-edge integration for CFETR

EAST steady-state long pulse H-mode with core-edge integration for CFETR

Recent advances in EAST physics experiments in support of steady-state operation for ITER and CFETR

Study on filament width of type-I ELM in EAST using VUV imaging system and simulation

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