A5072037821- Nuclear Physics and Applications
- Radiation Detection and Scintillator Technologies
- Nuclear reactor physics and engineering
- Magnetic confinement fusion research
- Radioactive contamination and transfer
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Catalytic Processes in Materials Science
- Nuclear and radioactivity studies
- Nuclear Materials and Properties
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Radioactive element chemistry and processing
- Geophysical Methods and Applications
- Radioactivity and Radon Measurements
- Heat Transfer and Boiling Studies
- Machine Learning in Materials Science
- Laser-Plasma Interactions and Diagnostics
- Electronic and Structural Properties of Oxides
- Solar and Space Plasma Dynamics
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Nuclear Engineering Thermal-Hydraulics
- Radiation Therapy and Dosimetry
Idaho National Laboratory
2014-2024
Thomas Jefferson National Accelerator Facility
2019
Colorado State University
2016
Rice University
2016
University of Georgia
2006-2010
Los Alamos National Laboratory
2009
Idaho State University
2006-2009
Oak Ridge National Laboratory
2009
Lawrence Livermore National Laboratory
2001
General Atomics (United States)
1993-1997
Peaked pressure profiles and central ion temperatures up to 20 keV are observed in DIII-D $H$-mode discharges with a region of strongly reversed magnetic shear. Short wavelength ballooning modes stabilized by access the second stable regime, longer conducting wall possibly rotational Values normalized beta, ${\ensuremath{\beta}}_{N}=\frac{\ensuremath{\beta}\mathrm{aB}}{I}$, 4 (%-$m$-T/MA), energy confinement factor 3 better than $L$ mode, at least 50% noninductive plasma current this regime...
DIII-D discharges with values of beta (the ratio plasma pressure to magnetic pressure) up 12.5% demonstrate that a resistive wall can stabilize low- $n$ magnetohydrodynamic (MHD) modes. In broad current profiles, exceeds the ideal MHD stability limit by at least factor 1.3 assuming no wall, but remains below calculated under assumptions vacuum vessel is perfectly conducting wall. Plasma rotation essential stabilization, and instabilities resembling predicted ``resistive mode'' appear only...
It is shown that the theoretical predictions and experimental observations of toroidicity-induced Alfvén eigenmodes (TAE’s) are now in good agreement, with particularly detailed agreement mode frequencies. Calculations driving damping rates predict importance continuum for low toroidal numbers this confirmed experimentally. However, calculations finite-β, shaped discharges existence other global modes, particular ellipticity-induced eigenmode (EAE) a new mode, beta-induced (BAE). The BAE...
Detailed analysis of recent high beta discharges in the DIII-D [Plasma Physics Controlled Nuclear Fusion Research, 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. I, p. 159] tokamak demonstrates that resistive vacuum vessel can provide stabilization low n magnetohydrodynamic (MHD) modes. The experimental values reaching up to βT=12.6% are more than 30% larger maximum stable calculated with no wall stabilization. Plasma rotation is essential for When plasma slows sufficiently,...
Deuterium gas injected into ELMing H mode divertor discharges in the DIII-D tokamak typically reduced total power at target ~2 times and peak heat flux ~3 to 5 with modest (<10%) degradation plasma energy confinement. The parameter range for investigated was: Ip=1.0-2.0 MA, q95 approximately= 2.4-6.0 input (≲20 MW. Most of this reduction occurred sudden formation a high density, highly radiating region located between outboard separatrix strike point X point. This behaviour is associated...
A detailed reexamination of the (110) surface structure rutile ${\mathrm{TiO}}_{2}$ has been carried out using first-principles total-energy methods. This investigation is in response to a recent high-precision quantitative low-energy electron diffraction (LEED-IV) measurement revealing certain significant discrepancies between experiment and previous theoretical calculations. We have able resolve these achieve excellent agreement with by judicious attention reducing computational...
This paper presents a simulation modelling study aimed at supporting capacity planning of kidney replacement therapy services offered to patients different stages failure. The model consists combined discrete-event (DES) and system dynamics (SD) model, representing two aspects care. SD represents the demand for care by disease progression in over time, whereas DES models provision including transplantation types dialysis either hospital or home. A facilitated approach is adopted engage with...
For prompt detection of large (&gt;1 kt) above-ground explosions, infrasound microphone networks and arrays are deployed at surveyed locations across the world. Denser regional local for smaller however, they limited in number often temporarily experiments. With expanded interest yield explosions targeted vulnerable areas such as population centers key infrastructures, need more dense has increased. An “attritable” (affordable, reusable, replaceable) flexible alternative can be provided...
A regime of improved H mode energy confinement, the VH mode, was obtained following boronization DIII-D Tokamak vacuum vessel. The gradual confinement improvement in is associated with expansion pedestal and reduction thermal diffusivity a region just inside pedestal. Disappearance density fluctuation bursts latter region. terminated rapid global loss which initiated by toroidal number, n approximately 5, consistent calculated instability to an edge localized ideal kink. extension E*B...
High confinement mode (H-mode) discharges with peaked toroidal current density profile (high internal inductance, ${\mathit{l}}_{\mathit{i}}$) and improved are obtained in the DIII-D tokamak by dynamically varying using a rapid elongation ramp technique. The improvement increases ${\mathit{l}}_{\mathit{i}}$ persists presence of edge-localized modes. plasma rotation corresponding radial electric field component also increase peakedness profile.
The VH-mode regime of high confinement has been observed in both DIII-D and JET. is characterized by thermal twice that seen H-mode, with the edge transport barrier penetrating deeper into plasma. Two mechanisms have identified as important achieving this level confinement. Expansion E*B velocity shear turbulence suppression zone allowing reductions local transport, while access to second ballooning stability allows avoidance or elimination ELMs which impede improvement. performance phase...
Current models of antineutrino production in nuclear reactors predict detection rates and spectra at odds with the existing body direct reactor measurements. High-resolution detectors operated close to compact research cores can produce new precision measurements useful testing explanations for these observed discrepancies involving underlying or physics. Absolute measurement 235U-produced spectrum provide additional constraints evaluating accuracy current future models, while relative...
Experiments to explore the long-time evolution of noninductive, high βp plasmas in DIII-D tokamak [Plasma Physics and Controlled Nuclear Fusion Research, 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159], have identified a new, quiescent, performance regime. The experiments were carried out at low current (400–800 kA) with medium power neutral beam injection (3–10 MW). This regime is characterized by q0 (≳2) moderate li(∼1.3). It reached slow relaxation profile, on...
A regime of improved H-mode energy confinement, VH-mode, is obtained in the DIII-D tokamak with adequate vessel conditioning. The confinement VH-mode consistent extension region high E*B velocity shear turbulence suppression zone further from plasma boundary. enhancement can be limited by ELMs, localized momentum transfer events, or operation at heating power low q. Energy improves increasing triangularity cross section and independent elongation. termination associated an edge kink mode...
By using small fluorinated ethers as models for perfluoropolyalkyl ether lubricants, we have been able to determine the effect of fluorine on bonding and orientation alkylethers adsorbed Cu(111) surface. The desorption energies determined by temperature-programmed orientations Fourier transform infrared absorption reflection spectroscopy (FT-IRAS). model compounds studied were dioxolane (CH2OCH2OCH2) perfluorodioxolane (CF2OCF2OCF2), diethyl ((CH3CH2)2O) perfluorodiethyl ((CF3CF2)2O),...