A5100754681- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- Diamond and Carbon-based Materials Research
- Radiation Detection and Scintillator Technologies
- Nuclear Materials and Properties
- Fault Detection and Control Systems
- Nuclear Engineering Thermal-Hydraulics
- Immune Cell Function and Interaction
- Advanced Fiber Laser Technologies
- Particle physics theoretical and experimental studies
- Magnetic Field Sensors Techniques
- Cardiac Imaging and Diagnostics
- Laser Design and Applications
- Gamma-ray bursts and supernovae
Korea Institute of Fusion Energy
2013-2024
Catholic University of Korea
2024
Korea Advanced Institute of Science and Technology
2000-2005
Disruption prediction and avoidance is a critical need for next-step tokamaks, such as ITER. Event Characterization Forecasting (DECAF) research fully automates analysis of tokamak data to determine chains events that lead disruptions forecast their evolution allowing sufficient time mitigation or complete the disruption. event related local rotating global magnetohydrodynamic (MHD) modes vertical instability are examined with warnings issued many off-normal physics events, including density...
Abstract This work introduces a novel technique that incorporates the bias contaminating magnetic coil measurements within model, building upon previous sensor fusion techniques of and Hall (Quercia et al 2022 Nucl. Fusion 62 106032; Arpaia 2021 Sensors 22 182). In pursuit sustainable thermo-nuclear fusion, precise drift-free field are essential for effective plasma control. Typically, control diagnosis in achieved through inductive sensors integrators, striving low noise fast sampling...
Abstract Magnetic islands (MIs), resulting from a magnetic field reconnection, are ubiquitous structures in magnetized plasmas. In tokamak plasmas, recent researches suggested that the interaction between an MI and ambient turbulence can be important for nonlinear evolution, but lack of detailed experimental observations analyses has prevented further understanding. Here, we provide comprehensive such as spreading into enhancement at reconnection site, elucidating intricate effects plasma on...
Tokamak discharges using the expanded boundary divertor in DIII-D device exhibit H-mode confinement. With neutral-beam power up to 6 MW, energy confinement remains comparable Ohmic value at a plasma current of 1 MA. Confinement is also independent density and toroidal field. increases with current, but exact functional dependence is, as yet, uncertain. These results show that H mode can be achieved reactor-compatible open configuration.
An extensive study of intrinsic and controlled non-axisymmetric field (δB) impacts in KSTAR has enhanced the understanding about physics its implications, particular, on resonant magnetic perturbation (RMP) power threshold (Pth) for L–H transition. The n = 1 was measured to remain as low δB/B0 ~ 4 × 10−5 even at high-beta plasmas (βN 2), which corresponds approximately 20% below targeted ITER tolerance level. As RMP edge-localized-modes (ELM) control, robust ELM-crash-suppression been not...
Abstract The fourth KSTAR campaign in 2011 concentrated on active edge-localized mode (ELM) control by various methods such as non-axisymmetric magnetic perturbations, supersonic molecular beam injection (SMBI), vertical jogs of the plasma column and edge electron heating. segmented in-vessel coil (IVCC) system is capable applying n ⩽ 2 perturbed field with different phasing among top, middle bottom coils. Application an = 1 showed a desirable ELM suppression result. Fast achieved...
Abstract Real-time disruption prediction and its mitigation of mega-ampere (MA) plasma experiments have been performed in the 2022 KSTAR carbon lower divertor condition. Disruption around 1 MA current has severely affected in-vessel components, especially through their high magnetic energy. In this study, we developed implemented a data-driven real-time detection model based on neural network (NN) control system (PCS). Additionally, to deal with specific instability only observed few 1.2...
Along with an expanded evaluation of the equilibrium operating space Korea Superconducting Tokamak Advanced Research, KSTAR, experimental equilibria most recent plasma discharges were reconstructed using EFIT code. In near-circular plasmas created in 2009, reached a stored energy 54 kJ maximum current 0.34 MA. Highly shaped near double-null configuration 2010 achieved H-mode clear edge localized mode (ELM) activity, and transiently up to 257 kJ, elongation 1.96 normalized beta 1.3. The 0.7...
Abstract A robust disruption mitigation system (DMS) requires accurate characterization of key timescales, one the most notable being thermal quench (TQ). Recent modelling shattered pellet injection (SPI) into ITER plasmas, using JOREK and INDEX, suggests long TQ durations (6 – 10 ms) slow cold front propagation due to large plasma size. If validated, these predictions would have an impact on desired parameters strategies for DMS. To resolve questions, a database SPI experiments from several...
Typical ELMy H-mode discharges have been obtained in the KSTAR tokamak with combined auxiliary heating of neutral beam injection (NBI) and electron cyclotron resonant (ECRH). The minimum external power required for L–H transition is about 0.9 MW a line-averaged density ∼2.0 × 1019 m−3. There clear indication increase threshold decreasing densities lower than ∼2 transitions typically occurred shortly after beginning plasma current flattop (Ip = 0.6 MA) period fast shaping to highly elongated...
Abstract The latest results of confinement and edge-localized mode (ELM) characteristics Korea Superconducting Tokamak Advanced Research (KSTAR) H-mode plasmas are reported. estimation fast ion contribution to the total stored energy, calculated by both NUBEAM ASTRA simulations, effective heating power is used derive thermal energy time ( τ E ,thermal ), which compared with a multi-machine database. measured threshold for L–H transition P thr ) as function density shows roll-over minimum...
Abstract Although gas breakdown phenomena have been intensively studied over 100 years, the mechanism in a strongly magnetized system, such as tokamak, has still obscured due to complex electromagnetic topologies. There widespread misconception that conventional model of unmagnetized system can be directly applied system. However, we found clear evidence existing theories cannot explain experimental results. Here, demonstrate underlying tokamaks, turbulent ExB mixing avalanche, which...
A time series of static nonlinear ferromagnetic calculations was performed to mimic the time-dependent modelling plasma start-up by assessing effects Incoloy 908 used in superconducting coil jackets Korea Superconducting Tokamak Advanced Research (KSTAR) device. Time-series a two-dimensional axisymmetric circuit model with enabled us find appropriate waveforms for KSTAR poloidal field currents that satisfied various requirements, such as formation and sustainment nulls, sufficient amount...
Initial H-mode operation of the Korea Superconducting Tokamak Advanced Research (KSTAR) is expanded to higher normalized beta and lower plasma internal inductance moving towards design target operation. As a key supporting device for ITER, an important goal KSTAR produce physics understanding MHD instabilities at long pulse with steady-state profiles, high beta, over wide range rotation profiles. An advance from initial significant increase in stored energy Wtot = 340 kJ, βN 1.9, which 75%...
Abstract Abnormal (deviating from the target) variations in plasma vertical position Z and current <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>I</mml:mi><mml:mtext>p</mml:mtext></mml:msub></mml:mrow></mml:math> (such as displacements, transient ‘spikes’ quenches) constitute common elements of a disruption, phenomenon that is to be mitigated, or ultimately avoided future reactor-relevant tokamaks. While these abnormalities are...
Abstract 3D nonlinear MHD simulations of neon-doped single shattered pellet injection (SPI) conducted with the JOREK code reveal rich physics during SPI-induced disruptions in KSTAR. In early phase, pressure-driven modes dominate, and perturbation plasma current is largely consistent Pfirsch–Schlüter current. As shards reach q = 1 surface, resistive perturbations by helical electron cooling start to temperature core begins collapse convective mixing density driven internal <mml:math...
Abstract Among various edge localized mode (ELM) crash control methods, only non-axisymmetric magnetic perturbations (NAMPs) yield complete suppression of ELM crashes beyond their mitigation, and thus attract more attention than others. No other devices except KSTAR, DIII-D, recently EAST have successfully achieved with NAMPs. The underlying physics mechanisms these successful suppressions in a field environment, however, still remain uncertain. In this work, we investigate the...
ECH-assisted start-up using trapped particle configuration (TPC) is firstly studied in a superconducting, conventional tokamak, KSTAR. First, improved and efficient TPC than field null (FNC) achieved by enhanced pre-ionization plasma quality. shows the broader operation window terms of poloidal quality deuterium prefill pressure that FNC. Surprisingly trapping enhances performance even with much lower ratio spherical torus. Reliability low investigated 0D evolution code, TECHP0D. Second,...
The variation of a magnetic braking profile by non-axisymmetric fields has been experimentally demonstrated and numerically validated in the KSTAR tokamak. Two types n = 2 non-resonant were applied changing relative phase field coils. One is even parity, which deeply penetrate into plasma core, other odd parity localized at edge. produced significantly different perturbed structures, thereby drove global edge-dominant toroidal rotation damping, respectively. These distinct profiles are...