A5025421447- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Nuclear reactor physics and engineering
- Spacecraft and Cryogenic Technologies
- Nuclear Materials and Properties
- Laser-induced spectroscopy and plasma
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Semiconductor materials and devices
- Metallurgical Processes and Thermodynamics
- Graphite, nuclear technology, radiation studies
- Gas Dynamics and Kinetic Theory
- Advanced Thermodynamic Systems and Engines
- Particle Accelerators and Free-Electron Lasers
- Electromagnetic Simulation and Numerical Methods
- Rocket and propulsion systems research
- Nuclear and radioactivity studies
- Nuclear Physics and Applications
- Advanced Data Storage Technologies
Oak Ridge National Laboratory
2015-2024
Japan External Trade Organization
2015
Princeton University
2015
University of Wisconsin–Madison
2008-2013
University of Evansville
2013
Lawrence Livermore National Laboratory
2011-2012
Princeton Plasma Physics Laboratory
2011
Fusion Academy
2011
Fusion (United States)
2011
Centre National de la Recherche Scientifique
2011
The SPARC tokamak is a critical next step towards commercial fusion energy. designed as high-field ( $B_0 = 12.2$ T), compact $R_0 1.85$ m, $a 0.57$ m), superconducting, D-T with the goal of producing gain $Q>2$ from magnetically confined plasma for first time. Currently under design, will continue path Alcator series tokamaks, utilizing new magnets based on rare earth barium copper oxide high-temperature superconductors to achieve high performance in device. achievable conservative...
Abstract The EMC3‐Eirene code is improved in many aspects. Ad hoc boundary conditions for intrinsic impurities at the SOL‐core interface are removed by implicitly coupling to a 1D core model. Non‐uniform cross‐field transport coefficients allowed new version. A particle splitting technique implemented improving Monte Carlo statistic low‐temperature ranges of most interest. Domain splitting, which was possible toroidal direction only, now feasible all three directions, facilitating mesh...
The availability of future fusion devices, such as a nuclear science facility or demonstration power station, greatly depends on long operating lifetimes plasma facing components in their divertors. ORNL is designing the Material Plasma Exposure eXperiment (MPEX), superconducting magnet, steady-state device to address material interactions reactors. MPEX will utilize new highintensity source concept based RF technology. This allow experiment cover entire expected conditions divertor reactor....
Owing to its high magnetic field, power, and compact size, the SPARC experiment will operate with divertor conditions at or above those expected in reactor-class tokamaks. Power exhaust this scale remains one of key challenges for practical fusion energy. Based on empirical scalings, peak unmitigated parallel heat flux is projected be greater than 10 GW m −2 . This nearly an order magnitude higher has been demonstrated date. Furthermore, Edge-Localized Mode (ELM) energy fluence projections...
Abstract Wendelstein 7-X (W7-X), the largest advanced stellarator, is built to demonstrate high power, performance quasi-continuous operation. Therefore, in recent campaign, experiments were performed prepare for long pulse operation, addressing three critical issues: development of stable detachment, control heat and particle exhaust, impact leading edges on plasma performance. The exhaust W7-X realized with help an island divertor, which utilizes large magnetic islands at boundary. This...
Abstract Experiments performed during strongly-shaped high-power diverted negative triangularity (NT) experiments in DIII-D achieved detached divertor conditions and a transient-free edge, showcasing the potential for application of NT to core-edge integrated reactor-like scenario providing first characterization parametric dependencies detachment onset. Detached will be required future devices mitigate heat fluxes. Access dissipative was investigated via an increase upstream density....
Abstract The ITER divertor design and performance assessment, primarily based on the SOLPS-4.3 burning plasma database (Pitts R. et al 2019 Nucl. Mater. Energy 20 100696), assumes use of beryllium (Be) as surface material injection gas from main chamber top. However, current baseline favors more toroidally symmetric sub-divertor region. This paper evaluates implications these assumptions for in fusion power operation phase. impact location ions mirrors hydrogen only low phase scenario shown...
Abstract The SOLPS-ITER code is utilized to analyze the boundary plasma associated with a fast-flow lithium (Li) divertor configuration in fusion nuclear science facility (FNSF) tokamak and identify operational regimes acceptable core conditions. Plasma transport from has been coupled liquid metal (LM) MHD/heat transfer model Li open-surface design assess its impact on scrape-off-layer (SOL) performance. Simulations only Neon (Ne) impurity seeding have conducted evaluate meeting FNSF demands...
Joint experiment/theory/modelling research has led to increased confidence in predictions of the pedestal height ITER. This work was performed as part a US Department Energy Research Target FY11 identify physics processes that control H-mode structure. The study included experiments on C-Mod, DIII-D and NSTX well interpretation experimental data with theory-based modelling codes. provides ability models for peeling–ballooning stability, bootstrap current, width scaling make correct...
Research on the National Spherical Torus Experiment, NSTX, targets physics understanding needed for extrapolation to a steady-state ST Fusion Nuclear Science Facility, pilot plant, or DEMO. The unique operational space is leveraged test theories next-step tokamak operation, including ITER. Present research also examines implications coming device upgrade, NSTX-U. An energy confinement time, τE, scaling unified varied wall conditions exhibits strong improvement of BTτE with decreased electron...
The Wendelstein 7-X (W7-X) optimized stellarator fusion experiment, which went into operation in 2015, has been operating since 2017 with an un-cooled modular graphite divertor. This allowed first divertor physics studies to be performed at pulse energies up 80 MJ, as opposed 4 MJ the phase, where five inboard limiters were installed instead of a This, and number other upgrades device capabilities, extension regimes higher plasma density, heating power, performance overall, e.g. setting new...
Abstract Spherical tokamaks (STs) present unique challenges and opportunities in the area of particle power exhaust, intensified due to their more compact sizes.
Substantial efforts are underway STs determine limits dissipative operational regimes advanced divertor solutions, including at MAST-U which provides access Super-X configuration.
Power balance, upper/lower asymmetries have been studied using SOLPS-ITER simulations divertor. 
A set with experimentally...
The application of static magnetic field perturbations to a tokamak plasma is observed alter the dynamics high-frequency bursting Alfv\'en modes that are driven unstable by energetic ions. In response with an amplitude $\ensuremath{\delta}B/B\ensuremath{\sim}0.01$ at boundary, mode reduced, frequency increased, and chirp smaller. For weaker character, perturbation induces temporary transition saturated continuous mode. Calculations perturbed distribution function indicate 3D affects orbits...
AbstractA new era of fusion research has started with ITER being constructed and DEMO for power demonstration on the horizon. However, nuclear science needs to be developed before can designed. One most crucial complex outstanding issues solved is plasma surface interaction (PSI) in hostile environment a reactor. Not only are materials exposed unprecedented steady-state transient fluxes, but they also neutron fluxes. Both ion fluxes will change micro-structure facing significantly even...
Plasma-facing component (PFC) geometries are evaluated for a Fusion Nuclear Science Facility (FNSF) design to find solutions that compatible with flowing liquid lithium components while satisfying requirements from the perspective of plasma and neutral particle transport. Flowing metal (LM) divertor systems offer important advantages due continual regeneration surface material, but may require modifications standard optimized tokamak designs. Scrape Off Layer Plasma Simulator International...
Abstract Time-dependent SOLPS-ITER simulations have been used to identify reduced models with the sparse identification of nonlinear dynamics (SINDy) method and develop model-predictive control boundary plasma state using main ion gas puff actuation. A series actuation sequences are input into produce a dynamic response in upstream divertor quantities. The SINDy is applied linear for electron density at outboard midplane <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Computational optimization has revolutionized the field of stellarator design. To date, optimizations have focused primarily on neoclassical confinement and ideal MHD stability, although limited other parameters also been performed. The purpose this paper is to outline a select set new concepts for that, when taken as group, present significant step forward in concept. One criticisms that leveled at existing methods design complexity resultant coils. Recently, coil code—COILOPT++, which uses...
The unmitigated heat flux in attached operation of a fusion power plant is predicted to be destructive any solid divertor surface. Detachment, whereby the plasma pressure drops significantly before reaching target thus greatly reducing and sputtering, will necessary ensure adequate lifetime facing components (PFCs). lithium vapor box aims detach via evaporating condensing surfaces. By near or at plate it closer main chamber, density gradient can created. This ties energy losses poloidal...
Abstract Tokamak operation at negative triangularity has been shown to offer high energy confinement without the typical disadvantages of edge pedestals (Marinoni et al 2021 Nucl. Fusion 61 116010). In this paper, we examine impurity transport in DIII-D diverted experiments. Analysis charge exchange recombination spectroscopy reveals flat or hollow carbon density profiles core, and times consistently shorter than times. Bayesian inferences coefficients based on laser blow-off injections...
Many scientific problems can be formulated as sparse regression, i.e., regression onto a set of parameters when there is desire or expectation that some the are exactly zero do not substantially contribute. This includes many in signal and image processing, system identification, optimization, parameter estimation methods such Gaussian process regression. Sparsity facilitates exploring high-dimensional spaces while finding parsimonious interpretable solutions. In present work, we illustrate...
Abstract The Material Plasma Exposure Experiment (MPEX) is being constructed at Oak Ridge National Laboratory to investigate critical fusion reactor issues, such as plasma–material interactions (PMIs) under reactor-relevant conditions and time scales. linear device Proto-MPEX was used a test bed address anticipated research development issues associated with heating scenarios establish the physics basis for MPEX. SOLPS-ITER code suite has been applied understand plasma neutral transport in...
The 3D edge transport code EMC3-EIRENE has been applied for the first time to NSTX spherical tokamak.A new disconnected double null grid developed allow simulation of plasma where radial separation inner and outer separatrix is less than characteristic widths (e.g.heat flux width) at midplane.Modeling results are presented both an axisymmetric case a magnetic field in n=3 configuration.In vacuum approximation perturbed consists wide region destroyed surfaces helical lobes which mixture long...
A set of new water-cooled divertor components is being designed for the Wendelstein 7-X stellarator to protect edges primary plasma facing during bootstrap current evolution (~ 40 s). These components, referred as scraper elements (SEs), will intercept field lines and associated heat flux that would otherwise overload main target in certain operational scenarios. The SEs are calculated experience peak fluxes ~15-16 MW/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...