Overview of recent progress in 3D field physics in KSTAR

Park, Gunyoung; In, Y.; Park, Jong‐Kyu; Ko, W. H.; Lee, Jae-Hyun; Kim, Minwoo; Shin, Giwook; Hahn, S.H.; Kim, SangKyeun; Yang, Seong Moo; Hu, Qiming; Rhee, T.; Choi, M.; Kim, Kimin; Lee, Hyung Ho; Jeon, Y.M.; Kim, Woong-Chae; Yoon, S.W.

doi:10.1007/s40042-022-00423-z

Cited by 7 publications

(11 citation statements)

References 110 publications

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“…Additionally, recent results from DIII-D [19-21] revealed an apparent toroidal rotation threshold for ELM suppression with RMP, and ELM suppression is lost (or achieved) when the toroidal rotation is below (or above) the threshold. Similarly, ELM suppression was achieved with a high toroidal rotation, , in KSTAR [22,23]. These experiments indicate that a high toroidal rotation may be beneficial for ELM control with RMP.…”

Section: Conclusion and Discussionmentioning

confidence: 53%

“…Recent results from DIII-D [19][20][21] revealed an apparent toroidal rotation threshold for ELM suppression with RMP, and ELM suppression is lost (or achieved) when toroidal rotation is below (or above) the threshold. Similarly, ELMs were also suppressed in experiments with a high toroidal rotation, , in KSTAR, but the rotation threshold remains unclear [22,23], whereas a lower plasma rotation was found to be favorable to access ELM suppression in EAST [11]. Extensive efforts [11,[19][20][21] in ELM control have found that an electron perpendicular rotation near the pedestal top close to zero is very critical for achieving strong ELM mitigation or suppression.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on the roles of equilibrium toroidal rotation during edge-localized mode mitigated by resonant magnetic perturbations

DONG 董,

CHEN 陈,

MOU 牟

et al. 2024

Plasma Sci. Technol.

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The effects of equilibrium toroidal rotation during edge localized mode (ELM) mitigated by resonant magnetic perturbations (RMP) are studied with the experimental equilibria of EAST tokamak based on the four-field model in BOUT++ code. As the two main parameters to decide the toroidal rotation profiles, rotation shear and magnitudes are separately scanned to investigate their roles in the impacts of RMPs on P-B modes. On the one hand, the results show that strong toroidal rotation shear is favorable to the enhancement of self-generated E×B shearing rate 〈ω_(E×B) 〉 with RMPs, leading to the significant ELM mitigation with RMP in the stronger toroidal rotation shear region. On the other hand, toroidal rotation magnitudes may affect the ELM mitigation through changing the penetration of the RMPs, more precisely the resonant components. RMPs can lead reductions on the pedestal energy loss through enhancing the multi-modes coupling in the turbulence transport phase. The shielding effects on RMPs increase with the toroidal rotation magnitude, leading the enhancement of multi-modes coupling with RMPs to be significantly weakened. Hence the reductions of pedestal energy loss by RMPs decreases with rotation magnitude. In brief, the results show that toroidal rotation plays duale roles in ELM mitigation with RMP through changing the shielding effects of plasma by rotation magnitude and affecting 〈ω_(E×B) 〉 by rotation shear, respectively. In the high toroidal rotation region, toroidal rotation shear is usually strong and hence plays the dominant role in the influence of RMP on P-B modes. While in the low rotation region, toroidal rotation shear is weak and has negligible impacts on P-B modes, and rotation magnitude plays the dominant role in the influence of RMPs on the P-B modes by changing the field penetration. Therefore, the duale roles of toroidal rotation leads that the stronger ELM mitigation with RMP may be achieved both in low toroidal rotation region and the relatively high rotation region that has strong rotation shear.

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Section: Conclusion and Discussionmentioning

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Investigation on the roles of equilibrium toroidal rotation during edge-localized mode mitigated by resonant magnetic perturbations

DONG 董,

CHEN 陈,

MOU 牟

et al. 2024

Plasma Sci. Technol.

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“…With the application of the PI-VM models, we could maximize the performance of existing hardware in the manufacturing fab and develop the index from the accumulated fab data [5]. Figure 1 is the schematics of the PI-VM algorithm adopted plasma processing system in the observed mass production fab.…”

Section: Introductionmentioning

confidence: 99%

“…In the observed fab, efficient management of the mass production fab and predictive control of the processes with in-situ monitoring of the plasma processes has been possible [4][5][6][7][8]. Based on these successful application experiences of the PI-VM, we challenged the establishment of a new design rule over the management and control of the plasma etching process itself.…”

Section: Introductionmentioning

confidence: 99%

Data-driven plasma science based plasma etching process design in OLED mass production referring to PI-VM

Park,

Seong,

Park

et al. 2024

Plasma Phys. Control. Fusion

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The production efficiencies of OLED (Organic Light Emitting Diode) displays and semiconductor manufacturing have been dramatically improving with the help of plasma physics and engineering technology by utilizing a process monitoring methodology based on physical domain knowledge. This domain knowledge consists of plasma-heating and sheath physics, plasma chemistry, and plasma-material surface reaction kinetics. They were applied to the PI-VM (Plasma Information based Virtual Metrology) algorithm with the plasma diagnostics and noticeably enhanced process prediction performance by parameterizing plasma information (PI) in various processes of OLED display and semiconductor manufacturing fabs. PI-VM has shown superior process prediction accuracy, which can trace the states of processing plasmas as an application of data-driven plasma science compared to the classical statistics and machine learning-based virtual metrologies; thus, various plasma processes have been managed and controlled with the help of the PI-VM models. More than this, we have adopted the PI-VM model to optimize the patterning architecture and plasma processes simultaneously. The best combination of the etching pattern structure and plasma condition was adjustable based on the detailed understanding of the angular distribution of sputtered atoms from the etching target surface and their interaction with the plasma sheath based on the PI-VM modeling for etching profile failure prediction.

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“…Experimental findings indicate that Type-I ELM suppression, employing low toroidal mode number RMPs such as n = 1 or 2, can be achieved in wide q 95 operational windows [8][9][10]. However, this suppression is often accompanied by substantial density pump-out and energy confinement degradation, which may hinder the attainment of high-Q performance in fusion reactors [7][8][9][10][11]. On the other hand, ELM suppression experiments using high-n RMPs have demonstrated considerable advantages, including a slight drop in the energy confinement and minor density pump-out relative to the ELMy H-mode phases and reduced core tungsten concentration, as well as the significant reduction of the steady-state divertor power fluxes combining the use of gas fueling and neon impurity seeding [12,13].…”

Section: Introductionmentioning

confidence: 99%

Extension of ELM suppression window using n = 4 RMPs in EAST

Xie

Sun

et al. 2023

Nucl. Fusion

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The q95 window for Type-I Edge Localized Modes (ELMs) suppression using n=4 even parity Resonant Magnetic Perturbations (RMPs) has been significantly expanded to a range from 3.9 to 4.8 in EAST, which is demonstrated to be reliable and repeatable over the last two years. This window is significantly wider than the previous one achieved using n=4 odd parity RMPs, which is around q95=3.7±0.1. Here, n represents the toroidal mode number of the applied RMPs and q95 is the safety factor at 95% of the normalized poloidal magnetic flux. During ELM suppression, there is only a slight drop in the plasma stored energy and density (≤10%). The comparison of changes in the pedestal profiles suggests that ELM suppression is achieved when the pedestal gradient is kept lower than a threshold. This wide q95 window for ELM suppression is consistent with the prediction made by MARS-F modeling prior to the experiment, which located it at one of the resonant q95 windows for plasma response. The Chirikov parameter taking into account plasma response near the pedestal top, which measures plasma edge stochasticity, significantly increases when q95 exceeds 4, mainly due to the denser neighboring rational surfaces. The modeling of plasma response reveals a strong coupling between resonant and non-resonant components across the pedestal region, which is a characteristic of the kink-peeling like response observed during RMP-ELM suppression in previous studies on EAST. These promising results demonstrate the reliability of ELM suppression using the n=4 RMPs in EAST and expand the physical understanding on ELM suppression mechanism.

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Overview of recent progress in 3D field physics in KSTAR

Cited by 7 publications

References 110 publications

Investigation on the roles of equilibrium toroidal rotation during edge-localized mode mitigated by resonant magnetic perturbations

Investigation on the roles of equilibrium toroidal rotation during edge-localized mode mitigated by resonant magnetic perturbations

Data-driven plasma science based plasma etching process design in OLED mass production referring to PI-VM

Extension of ELM suppression window using n = 4 RMPs in EAST

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