A5029101480- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- Spacecraft and Cryogenic Technologies
- Physics of Superconductivity and Magnetism
- Nuclear Physics and Applications
- Pulsars and Gravitational Waves Research
- Machine Learning and ELM
- Inertial Sensor and Navigation
- Robotics and Automated Systems
- Spectroscopy and Laser Applications
- Random lasers and scattering media
- Hybrid Renewable Energy Systems
- Electron and X-Ray Spectroscopy Techniques
- Radiation Detection and Scintillator Technologies
- Medical Imaging and Analysis
- Dust and Plasma Wave Phenomena
- Laser-induced spectroscopy and plasma
Princeton Plasma Physics Laboratory
2020-2024
Princeton University
2023-2024
Seoul National University
2016-2020
Pohang University of Science and Technology
2017
Abstract The path of tokamak fusion and International thermonuclear experimental reactor (ITER) is maintaining high-performance plasma to produce sufficient power. This effort hindered by the transient energy burst arising from instabilities at boundary plasmas. Conventional 3D magnetic perturbations used suppress these often degrade performance increase risk other instabilities. study presents an innovative field optimization approach that leverages machine learning real-time adaptability...
A tokamak relies on the axisymmetric magnetic fields to confine fusion plasmas and aims deliver sustainable clean energy. However, misalignments arise inevitably in construction, leading small asymmetries field known as error (EFs). The EFs have been a major concern approaches because EFs, even less than 0.1%, can drive plasma disruption. Meanwhile, be favorably used for controlling instabilities, such edge-localized modes (ELMs). Here we show an optimization that tailors maintain edge 3D...
We report the status of hybrid scenario experiments in Korea Superconducting Tokamak Advanced Research (KSTAR). The is defined as stationary discharges with B N >= 2.4 and H_89 2.0 at q_95 < 6.5 without or very mild sawtooth activities KSTAR. It being developed towards reactor-relevant conditions. High performance
A newly developed plasma response model, combining the nonlinear two-fluid MHD code TM1 and toroidal GPEC run in ideal mode, quantitatively predicts narrow isolated q95 windows (Δq95 ∼ 0.1) of edge-localized mode (ELM) suppression by n = 1, 2, 3 resonant magnetic perturbations (RMPs) both DIII-D KSTAR tokamaks across a wide range parameters. The key physics that unites experimental observations our simulations is close alignment essential q-surfaces location top pedestal prior to an ELM....
Abstract A tokamak, a torus-shaped nuclear fusion device, needs an electric current in the plasma to produce magnetic field poloidal direction for confining plasmas. Plasma is conventionally generated by electromagnetic induction. However, steady-state reactor, minimizing inductive essential extend tokamak operating duration. Several non-inductive drive schemes have been developed operations such as radio-frequency waves and neutral beams. commercial reactors require minimal use of these...
Abstract A subspace of resonant magnetic perturbation (RMP) configurations for edge localized mode (ELM) suppression is predicted H-mode burning plasmas at 15 MA current and 5.3 T field in ITER. Perturbations to the core plasma can be reduced by a factor 2 equivalent stability proxies, while perturbed boundary geometry remains mostly resilient. The striated domain lines connecting from main (normalized poloidal flux <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
An external 3D magnetic perturbation typically drives a resonant response at the rational surfaces from core to edge of tokamak plasmas, due strong mode coupling and amplification. This paper presents method isolate fields using ideal perturbed equilibrium code design an edge-localized (RMP) for effective localized (ELM) control. A robust feature RMP is curtailed field low-field-side (LFS) midplane, as opposed typical RMPs which strongly resonate with LFS fields. emphasizes importance...
Abstract The integrated Resonant Magnetic Perturbation (RMP)-based Edge-Localized Mode (ELM)-crash-control process aims to enhance the plasma performance during RMP-driven ELM crash suppression, where RMP induces an unwanted confinement degradation. In this study, normalized beta ( <?CDATA $\beta_\textrm{N}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>β</mml:mi> <mml:mrow> <mml:mtext>N</mml:mtext> </mml:mrow> </mml:msub> </mml:math> ) is...
Abstract The Korean Superconducting Tokamak Advanced Research has been focused on exploring the key physics and engineering issues for future fusion reactors by demonstrating long pulse operation of high beta steady-state discharge. scenarios are being developed with goal operation, significant progress made in ℓ i , hybrid β N 3. In new scenario called fast ion regulated enhanced (FIRE), ions play an essential role confinement enhancement. GK simulations show a reduction thermal energy flux...
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Abstract This large database study of RMP ELM suppression thresholds in the AUG, DIII-D, EAST, and KSTAR tokamaks details key strengths weaknesses resonant magnetic perturbation (RMP) metrics. The used for this work contains plasma information at time transition from ELMing to suppressed states where a clear experimental threshold is identified. distributions are compared 5 metrics: (1) island overlap width, (2) pedestal top Chirikov overlap, (3) peeling edge displacement, (4) drive, (5)...
Experiments of electron cyclotron resonance heating (ECH) power scan in KSTAR tokamak clearly demonstrate that both the cut-off density for non-local heat transport (NLT) and threshold intrinsic rotation reversal can be determined by collisionality. We NLT affected ECH, direction follows changes NLT. The significantly extended ECH. poloidal flow turbulence core plasma is ion diamagnetic ECH plasmas high OH plasma, respectively. auto-power spectra fluctuation are almost same outer region...
Operation of a fusion power plant requires robust edge localized mode (ELM) suppression simultaneously with high plasma performance. In this paper, we describe novel feedback adaptive resonant magnetic perturbation (RMP) ELM controller designed to address problem by achieving optimized through the advanced application 3D RMPs. From real-time Dα data, is able achieve while minimizing applied RMP in order enhance real-time, instantaneous ELM-frequency analyzed an algorithm determine amplitudes...
Abstract Two types of experiments were carried out to conduct an intrinsic rotation study in KSTAR. The first was a density ramp-up experiment without neutral beam injection, and the second with blip technique. In these experiments, some characteristics observed KSTAR Ohmic L-mode plasmas including: (i) non-monotonic dependence core rotation, called U-curve behaviour, respect electron collisionality related gradient toroidal profile; (ii) behaviour anchor point profile for which region...
Transport of α particles due to trapped electron mode (TEM) turbulence is investigated from nonlinear and quasilinear gyrokinetic simulations. We consider both slowing-down Maxwellian distribution functions for identify compare diffusive convective parts particle transport as a function the particle's energy normalized background plasma temperature. find that TEM induces much lower energetic such fusion products than thermal Helium ions in trace limit. This disparity our study found be even...
Abstract Fully suppressing edge-localized modes (ELMs), e.g., with resonant magnetic perturbations (RMPs), is essential to reach and sustain high-performance steady-state H-mode plasmas because large ELMs can significantly reduce the lifetime of divertor components in future tokamak reactors. RMP-driven ELM suppression KSTAR has been modeled by coupling neoclassical transport code PENTRC nonlinear 3D MHD JOREK. We have found that radial from combined effects kink-peeling, tearing response,...
A small nonaxisymmetric (3D) magnetic field can induce nonambipolar transport of the particle species confined in a tokamak and thus significant change plasma rotation. This process be favor instability control region where is sufficiently collisional resistive, as observed applications n=1 resonant perturbations to KSTAR tokamak. The rotation globally accelerated due radially drifting electrons constrained electron root, if radial enhanced by an amplified 3D response. mechanism verified...
Abstract Mitigation of deleterious heat flux from edge-localized modes (ELMs) on fusion reactors is often attempted with 3D perturbations the confining magnetic fields. However, established technique resonant (RMPs) also degrades plasma performance, complicating implementation future reactors. In this paper, we introduce an adaptive real-time control scheme KSTAR tokamak as a viable approach to achieve ELM-free state and simultaneously recover high-confinement ( β N ∼ 1.91, p 1.53, H 98...
The striation pattern of heat loads on the divertor targets is determined by plasma response to external resonant magnetic perturbations (RMPs) applied for suppression edge localized modes (ELMs). Ideal and kinetic analysis with general perturbed equilibrium code (GPEC) has shown that extent this very sensitive radial location truncation in GPEC, a significantly smaller found if truncated closer separatrix. Depending choice truncation, it EMC3-EIRENE simulations peak load can be reduced...
Abstract This paper deals with one of the origins and trigger mechanisms responsible for observed performance enhancements in hybrid scenario experiments conducted Korea Superconducting Tokamak Advanced Research (KSTAR). The major contribution to improvement comes from a broader higher pedestal formation. increase fast ion pressure due plasma density decrease also contributes substantially global beta. Although reduced core volume resulting expansion has negative effect on thermal energy,...
Abstract 3D resonant magnetic perturbation (RMP) is one promising way to control edge localized modes that can cause excessive material erosion of tokamak first walls. However, RMP lead undesired degradation plasma confinement, including fast-particle losses, which impact the performance and safety reactor. This work investigates optimization poloidal spectrum field optimize fast ion confinement during mode (ELM) suppression. In initial step, validity modeling framework tested against...
Predictive 3D optimization reveals a novel approach to modify nonaxisymmetric magnetic perturbation be entirely harmless for tokamaks, by essentially restoring quasisymmetry in perturbed particle orbits as much possible. Such quasisymmetric (QSMP) has been designed and successfully tested the KSTAR DIII-D demonstrating no performance degradation despite large overall amplitudes of fields strong response otherwise expected plasmas. The results indicate that is robust path error field...