D.G. Whyte
A5087664822- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Nuclear Materials and Properties
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Ion-surface interactions and analysis
- Laser-induced spectroscopy and plasma
- Metal and Thin Film Mechanics
- Semiconductor materials and devices
- Physics of Superconductivity and Magnetism
- Diamond and Carbon-based Materials Research
- Combustion and Detonation Processes
- Dust and Plasma Wave Phenomena
- Advanced Data Storage Technologies
- Atomic and Molecular Physics
- Nuclear Engineering Thermal-Hydraulics
- Solar and Space Plasma Dynamics
- Advanced materials and composites
- Silicon and Solar Cell Technologies
- High-Velocity Impact and Material Behavior
Massachusetts Institute of Technology
2013-2024
Plasma Technology (United States)
2014-2024
Fusion (United States)
2014-2024
Fusion Academy
2014-2024
University of Wisconsin–Madison
2003-2014
University of California, Los Angeles
2014
General Atomics (United States)
1995-2014
Princeton Plasma Physics Laboratory
2009-2014
IIT@MIT
2007-2014
University of California, San Diego
1998-2010
The major increase in discharge duration and plasma energy a next step DT fusion reactor will give rise to important plasma-material effects that critically influence its operation, safety performance. Erosion scale of several centimetres from being barely measurable at micron today's tokamaks. Tritium co-deposited with carbon strongly affect the operation machines facing components. Controlling plasma-wall interactions is critical achieving high performance present day tokamaks, this likely...
Progress in the area of MHD stability and disruptions, since publication 1999 ITER Physics Basis document (1999 Nucl. Fusion 39 2137–2664), is reviewed. Recent theoretical experimental research has made important advances both understanding control tokamak plasmas. Sawteeth are anticipated baseline ELMy H-mode scenario, but tools exist to avoid or them through localized current drive fast ion generation. Active other instabilities will most likely be also required ITER. Extrapolation from...
Progress, since the ITER Physics Basis publication (ITER Editors et al 1999 Nucl. Fusion 39 2137–2664), in understanding processes that will determine properties of plasma edge and its interaction with material elements is described. Experimental areas where significant progress has taken place are energy transport scrape-off layer (SOL) particular anomalous scaling, particle SOL plays a major role diverted plasmas main-chamber elements, localized mode (ELM) deposition on mechanism for ELM...
An improved energy confinement regime, I-mode, is studied in Alcator C-Mod, a compact high-field divertor tokamak using ion cyclotron range of frequencies (ICRFs) auxiliary heating. I-mode features an edge transport barrier without accompanying particle barrier, leading to several performance benefits. H-mode obtained core impurity accumulation, resulting reduced radiation with high-Z metal wall and ICRF has stationary temperature pedestal localized modes typically absent, while plasma...
Abstract The SPARC tokamak project, currently in engineering design, aims to achieve breakeven and burning plasma conditions a compact device, thanks new developments high-temperature superconductor technology. With magnetic field of 12.2 T on axis 8.7 MA current, is predicted produce 140 MW fusion power with gain Q ≈ 11, providing ample margin respect its mission > 2. All systems are being designed this landmark discharge, thus enabling the study physics operations reactor relevant pave...
The SPARC Toroidal Field Model Coil (TFMC) Program was a three-year effort between 2018 and 2021 that developed novel Rare Earth Barium Copper Oxide (REBCO) superconductor technologies then successfully utilized these to design, build, test first-in-class, high-field (∼20 T), representative-scale (∼3 m) superconducting toroidal field (TF) coil. program executed jointly by the MIT Plasma Science Fusion Center (PSFC) Commonwealth Systems (CFS) as technology enabler of pathway fusion energy,...
The SPARC Toroidal Field Model Coil (TFMC) is the first large-scale (∼3 m), high-field (∼20 T) superconducting fusion magnet based on Rare Earth Yttrium Barium Copper Oxide (REBCO). Its objective was to retire risk for toroidal field in tokamak, a burning plasma class magnetic confinement energy device. Weighing 10,058 kg and utilizing 270 km of REBCO, TFMC non-insulated, stack-in-plate style magnet. It has three main components: (1) winding pack; (2) structural case; (3) case extensions, or...
Intermittent plasma objects (IPOs) featuring higher pressure than the surrounding plasma, and responsible for ∼50% of E×BT radial transport, are observed in scrape off layer (SOL) edge DIII-D tokamak [J. Watkins et al., Rev. Sci. Instrum. 63, 4728 (1992)]. Conditional averaging reveals that IPOs, produced at a rate ∼3×103 s−1, positively charged also polarized, poloidal electric fields up to 4000 V/m. The IPOs move poloidally speeds 5000 m/s radially with E×BT/B2 velocities ∼2600 near last...
Intermittent plasma objects (IPOs), featuring higher pressure than the surrounding plasma, are responsible for ∼50% of E×BT radial transport in scrape off layer (SOL) Doublet III D (DIII-D) tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] L- and H-mode discharges. Conditional averaging reveals that IPOs positively charged feature internal poloidal electric fields up to 4000 V/m. The move radially with E×BT/B2 velocities ∼2600 m/s near last closed flux surface (LCFS), ∼330 wall. slow down...
Recent research in scrape-off layer (SOL) and divertor physics is reviewed; new existing data from a variety of experiments have been used to make cross-experiment comparisons with implications for further ITER. Studies the region near separatrix addressed relationship profiles turbulence as well scaling parallel power flow. Enhanced low-field side radial transport implicated driving flows inboard side. The medium-n nature edge localized modes (ELMs) has elucidated measurements determined...
High-resolution charge-exchange recombination spectroscopic measurements of B5+ ions have enabled the first spatially resolved calculations radial electric field (Er) in Alcator C-Mod pedestal region [E. S. Marmar, Fusion Sci. Technol. 51, 261 (2006)]. These observations offer new challenges for theory and simulation provide important comparisons with other devices. Qualitatively, structure observed on is similar to that tokamaks. However, narrow high-confinement mode (H-mode) Er well widths...
Abstract Growth of tungsten nano-tendrils (‘fuzz’) has been observed for the first time in divertor region a high-power density tokamak experiment. After 14 consecutive helium L-mode discharges Alcator C-Mod, tip Langmuir probe at outer strike point was fully covered with layer nano-tendrils. The thickness individual (50–100 nm) and depth (600 ± 150 are consistent observations from experiments on linear plasma devices. observation fuzz may have important implications material erosion, dust...
The goal of the Lower Hybrid Current Drive (LHCD) system on Alcator C-Mod tokamak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] is to investigate current profile control under plasma conditions relevant future experiments. Experimental observations a LHCD "density limit" for are presented in this paper. Bremsstrahlung emission from relativistic fast electrons core drops suddenly above line averaged densities 1020 m−3 (ω/ωLH∼3–4), well below density limit previously observed other...
Three advanced nuclear power systems use liquid salt coolants that generate tritium and thus face the common challenges of containing capturing to prevent its release environment. The fluoride salt–cooled high-temperature reactor (FHR) uses clean same graphite-matrix coated-particle fuel as gas-cooled reactors. Molten reactors (MSRs) dissolve in a or chloride with fission product into salt. In most FHR MSR systems, baseline salts contain lithium where isotopically separated 7Li is proposed...
The object of this review is to summarize the achievements research on Alcator C-Mod tokamak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994) and Marmar, Fusion Sci. Technol. 51, 261 (2007)] place that in context quest for practical fusion energy. a compact, high-field tokamak, whose unique design operating parameters have produced wealth new important results since it began operation 1993, contributing data extends tests critical physical models into parameter ranges regimes. Using only...
The SPARC Toroidal Field Model Coil (TFMC) experimental tests are described. include detailed comparisons to a hierarchy of electromagnetic and structural models the coil. confirmed ability no-insulation no-twist (NINT) configuration provide highly stable DC operations with peak magnetic field in excess 20 tesla at REBCO tape stacks. advantages modular TFMC approach were validated including test probe response coil stages; strategy that will be applied large-scale production for SPARC....
The sputtering yields of molybdenum, titanium, beryllium, and carbon have been measured during xenon ion bombardment from a plasma in the energy range between 10 200 eV. erosion rates Mo, Be, C are both spectroscopically using standard weight loss technique. Spectroscopic measurements Ti yields, where no atomic physics data is available, normalized to measurements. metals decrease with reduced mass metal–xenon combination increasing metal’s binding energy, as expected. results for graphite...
Cross-field fluctuation-driven transport is studied in edge and scrape-off layer (SOL) plasmas the DIII-D tokamak using a fast reciprocating Langmuir probe array allowing local measurements of particle heat fluxes. Two different non-diffusive mechanisms that can contribute strongly to cross-field SOL high-density discharges are identified compared. The first these involves intermittent events observed at plasma separatrix SOL. Intermittence has qualitatively similar character L-mode ELM-free...
New experimental results on transient loads during ELMs and disruptions in present divertor tokamaks are described used to carry out a extrapolation ITER reference conditions draw consequences for its operation. In particular, the achievement of low energy/convective type I edge localized modes (ELMs) ITER-like plasma seems only way obtain which may be compatible with an acceptable erosion lifetime facing components (PFCs) ITER. Power disruptions, contrary, seem lead most cases because...
High-pressure gas-jet injection of neon and argon is shown to be a simple robust method mitigate the deleterious effects disruptions on DIII-D tokamak. The gas jet penetrates central plasma at its sonic velocity. deposited species dissipates >95% by radiation substantially reduces mechanical stresses vessel caused poloidal halo currents. species-charge distribution can include >50% fraction neutral which inhibits runaway electrons. favorable scaling this technique burning fusion plasmas discussed.
Far Scrape-Off Layer (SOL) and near-wall plasma parameters in DIII-D depend strongly on the discharge confinement regime. In L-mode discharges cross-field transport increases with average density flattens far SOL profiles, thus increasing contact low field side (LFS) main chamber wall. H-mode between edge localized modes (ELMs) plasma–wall is weaker than L-mode. During ELM fluxes of particles heat to LFS wall increase transiently above values. Depending conditions, ELMs are responsible for...
We report extended studies of the I-mode regime [Whyte et al., Nucl. Fusion 50, 105005 (2010)] obtained in Alcator C-Mod tokamak [Marmar Sci. Technol. 51(3), 3261 (2007)]. This regime, usually accessed with unfavorable ion B × ∇B drift, features an edge thermal transport barrier without a strong particle barrier. Steady I-modes have now been favorable by using specific plasma shapes, as well drift over wider range shapes and parameters. With power thresholds are close to standard scaling for...
A potentially attractive next-step towards fusion commercialization is a pilot plant, i.e. device ultimately capable of small net electricity production in as compact facility possible and configuration scalable to full-size power plant. key capability for pilot-plant programme the high neutron fluence enabling nuclear science technology (FNST) research. It found that physics assumptions between those assumed ITER nth-of-a-kind it provide FNST-relevant wall loading devices. Thus, may be...