A5041734008- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Shakespeare, Adaptation, and Literary Criticism
- Solar and Space Plasma Dynamics
- Gyrotron and Vacuum Electronics Research
- Nuclear Physics and Applications
- Metal and Thin Film Mechanics
- Laser-induced spectroscopy and plasma
- Dust and Plasma Wave Phenomena
- Diamond and Carbon-based Materials Research
- Electrostatic Discharge in Electronics
- Semiconductor materials and devices
- Nuclear reactor physics and engineering
- Nuclear Materials and Properties
- Reformation and Early Modern Christianity
- Laser Design and Applications
- Physics of Superconductivity and Magnetism
- Social Policy and Reform Studies
- Fusion and Plasma Physics Studies
Lawrence Livermore National Laboratory
2001-2024
Princeton University
2006-2022
Princeton Plasma Physics Laboratory
2011-2022
KLE Society Hospital
2018
Sir Ganga Ram Hospital
2018
Plasma Technology (United States)
2000-2016
Fusion Academy
2000-2016
Fusion (United States)
2000-2016
Bial (Portugal)
2016
The University of Texas at Austin
2016
Neutral-beam heating of plasmas in the Tokamak Fusion Test Reactor at low preinjection densities [${n}_{e}$(0)\ensuremath{\simeq}${10}^{19}$ ${\mathrm{m}}^{\mathrm{\ensuremath{-}}3}$] were characterized by ${T}_{e}$(0)=6.5 keV, ${T}_{i}$(0)=20 ${n}_{e}$(0)=7\ifmmode\times\else\texttimes\fi{}${10}^{19}$ ${\mathrm{m}}^{\mathrm{\ensuremath{-}}3}$, ${\ensuremath{\tau}}_{E}$=170 msec, ${\ensuremath{\beta}}_{\mathrm{theta}}$=2, and a d(d,n${)}^{3}$He neutron emission rate ${10}^{16}$...
Shakespeare is regarded as a pillar of culture in the English-speaking world. The questions posed by this book are why so and does he deserve such acclaim? This which challenges very ground literary judgement.
Abstract The spherical tokamak (ST) is a leading candidate for Fusion Nuclear Science Facility (FNSF) due to its compact size and modular configuration. National Spherical Torus eXperiment (NSTX) MA-class ST facility in the US actively developing physics basis an ST-based FNSF. In plasma transport research, experiments exhibit strong (nearly inverse) scaling of normalized confinement with collisionality, if this trend holds at low high fusion neutron fluences could be achievable very...
Turbulent fluctuations in plasmas with reversed magnetic shear have been investigated on the Tokamak Fusion Test Reactor. Under intense auxiliary heating, these are observed to bifurcate into two states different transport properties. In state better confinement, it has found that level of is very small throughout most region negative shear. By contrast, lower confinement characterized by large bursts which suggest a competition between driving and suppression turbulence. These results...
Simultaneous profile measurements of the toroidal rotation speed and ion temperature during unbalanced neutral beam injection in Tokamak Fusion Test Reactor show that momentum thermal diffusivities are comparable magnitude (${\mathrm{\ensuremath{\chi}}}_{\mathrm{\ensuremath{\varphi}}}$\ensuremath{\approxeq}1.5${\mathrm{\ensuremath{\chi}}}_{\mathrm{i}}$) vary similarly with plasma current minor radius. The correlation ${\mathrm{\ensuremath{\chi}}}_{\mathrm{\ensuremath{\varphi}}}$...
Neutral-beam--heated plasmas in TFTR show evidence of substantial non-Ohmically driven toroidal current, even for balanced beam momentum input. The observations are inconsistent with calculations including only Ohmic and beam-driven currents, presently can be matched by models the neoclassical bootstrap current.
Off-axis sawteeth are often observed in reversed magnetic shear plasmas when the minimum safety factor $q$ is near or below 2. Fluctuations with $m/n\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2/1$ ( $m$ and $n$ poloidal toroidal mode numbers) appear before after crashes. Detailed comparison has been made between measured ${T}_{e}$ profile evaluation during crash a nonlinear numerical magnetohydrodynamics simulation. The good agreement observation simulation indicates that off-axis...
Journal Article Gary Taylor. Reinventing Shakespeare: A Cultural History, from the Restoration to Present Get access Present. By New York: Weidenfeld and Nicolson, 1989. Pp. 461. $29.95 cloth. Margreta De Grazia Search for other works by this author on: Oxford Academic Google Scholar Shakespeare Quarterly, Volume 41, Issue 4, Winter 1990, Pages 524–527, https://doi.org/10.2307/2870785 Published: 01 December 1990
Experiments in the National Spherical Torus Experiment (NSTX) have shown beneficial effects on performance of divertor plasmas as a result applying lithium coatings graphite and carbon-fiber-composite plasma-facing components. These mostly been applied by pair evaporators mounted at top vacuum vessel which inject collimated streams vapor toward lower divertor. In neutral beam injection (NBI)-heated deuterium H-mode run immediately after application lithium, modifications included decreases...
The time-scales for sawtooth repetition and heat pulse propagation are much longer (tens of milliseconds) in the large tokamak TFTR than previous, smaller tokamaks. This extended time-scale, coupled with more detailed diagnostics, has led us to revisit analysis as a method determine electron diffusivity χe plasma. A combination analytic computer solutions diffusion equation is used clarify previous work develop new methods determining χe. Direct comparison predicted pulses soft-X-ray ECE...
The development of noninductive current drive is great importance in establishing the tokamak as a long-pulse or steady-state fusion reactor. Lower hybrid waves, carrying 200 kW power at 800 MHz, have been launched into Princeton Large Torus to initiate and discharge level excess 100 kA.
Alpha-particle-driven toroidal Alfvén eigenmodes (TAEs) have been observed for the first time in deuterium-tritium (D-T) plasmas on tokamak fusion test reactor (TFTR). These modes are 100–200 ms following end of neutral beam injection with reduced central magnetic shear and elevated safety factor [q0>1]. Mode activity is localized to region discharge r/a<0.5 fluctuation level B̃⊥/B∥∼10−5 mode numbers range n=2–4, consistent theoretical calculations α-TAE stability TFTR.Received 11 November...
The relaxation of core transport barriers in TFTR enhanced reversed shear plasmas has been studied by varying the radial electric field using different applied torques from neutral beam injection. Transport rates and fluctuations remain low over a wide range shear, but increase when local $\mathbf{E}\ifmmode\times\else\texttimes\fi{}\mathbf{B}$ shearing are driven below threshold comparable to fastest linear growth dominant instabilities. Shafranov-shift-induced stabilization alone is not...
The roles of turbulence stabilization by sheared E×B flow and Shafranov shift gradients are examined for Tokamak Fusion Test Reactor [D. J. Grove D. M. Meade, Nucl. 25, 1167 (1985)] enhanced reverse-shear (ERS) plasmas. Both effects in combination provide the basis a positive-feedback model that predicts reinforced suppression with increasing pressure gradient. Local fluctuation behavior at onset ERS confinement is consistent this framework. power required transitions into regime lower when...
Measurements on the TFTR tokamak of electron-temperature-profile evolution and soft-x-ray emissivity a fast (10-\ensuremath{\mu}sec) time scale during sawtooth crash show that significant heat is deposited beyond mixing (or reconnection) radius within 200 \ensuremath{\mu}sec following crash. This extended region in which electron redistributed substantially complicates determination transport properties from subsequent pulse propagation. It shown relaxation this perturbation consistent with...
AbstractMicrowave-based diagnostics have found broad application in magnetic fusion plasma and are expected to be widely employed future burning experiments (BPXs). Most of these techniques based directly on the dispersive properties medium that, as shown body paper, results microwave/millimeter wave portion electromagnetic spectrum being particularly well suited for a variety measurements both equilibrium parameters their fluctuations. Electron cyclotron emission provides measurement...
High harmonic fast wave heating and current drive (CD) are being developed on the National Spherical Torus Experiment [M. Ono et al., Nucl. Fusion 41, 1435 (2001)] for supporting startup sustainment of spherical torus plasma. Considerable enhancement core efficiency (η) from 44% to 65% has been obtained CD phasing antenna (strap-to-strap ϕ=−90°, kϕ=−8m−1) by increasing magnetic field 4.5to5.5kG. This increase in is strongly correlated moving location onset density perpendicular propagation...
A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost the scrape-off layer (SOL) and deposited in bright hot spirals on divertor rather than core plasma. We show that HHFW flows these along magnetic field lines passing through SOL front antenna, implying couples across entire width mostly at antenna face. This result will help guide future efforts understand minimize edge losses order maximize heating current drive.
Deuterium high-confinement (H-mode) plasmas, lasting up to 3.45 s, have been generated in the EAST by ion cyclotron range of frequency (ICRF) heating. H-mode access was achieved coating molybdenum-tiled first wall with lithium reduce hydrogen recycling from wall. plasmas plasma currents between 0.4 and 0.6 MA axial toroidal magnetic fields 1.85 1.95 T were 27 MHz ICRF heating deuterium minority. The input power required 1.6–1.8 MW. line-averaged density (1.83–2.3) × 1019 m−3. 200–500 Hz...
The National Spherical Torus Experiment (NSTX) has undergone a major upgrade, and the NSTX Upgrade (NSTX-U) Project was completed in summer of 2015.NSTX-U first plasma subsequently achieved, diagnostic control systems have been commissioned, H-mode accessed, magnetic error fields identified mitigated, physics research campaign carried out.During ten run weeks operation, NSTX-U surpassed record pulse-durations toroidal (TF), high-performance ~1 MA plasmas comparable to best sustained near...
The bremsstrahlung emission from the PLT tokamak during lower-hybrid current drive has been measured as a function of angle between magnetic field and direction. is peaked strongly in forward direction, indicating strong anisotropy electron velocity distribution. data demonstrate existence nearly flat tail distribution, which extends out to approximately 500 keV interpreted plateau created by Landau damping waves.
Lower-hybrid current drive requires the generation of a high-energy electron tail anisotropic in velocity. Measurements bremsstrahlung emission produced by this are compared with calculated from reasonable model distributions. The physical basis and sensitivity modelling process described, plasma properties current-driven discharges which can be derived discussed.
The properties of a steady-state, dc discharge multidipole ion source have been investigated. plasma density in the depends on magnet geometries, voltage, and bias voltage first extraction grid. Different schemes to reduce loss ions chamber wall are described. Hydrogen species extracted beam studied by mass analyzer.
Full wave simulations of fusion plasmas show a direct correlation between the location fast-wave cut-off, radiofrequency (RF) field amplitude in scrape-off layer (SOL) and RF power losses SOL observed National Spherical Torus eXperiment (NSTX). In particular, increase significantly when launched waves transition from evanescent to propagating that region. Subsequently, large electric occurs SOL, driving proxy collisional loss term is added. A 3D reconstruction absorbed presented showing...
Studies of the enhanced Dα H-mode (EDA) have been extended to include ohmic plasmas. No clear difference in EDA/ELMfree boundary or other phenomenology are seen between and ICRF-heated plasmas, suggesting that neither effect ion tails nor direct RF/edge plasma interaction plays a role EDA. Edge safety factor (q95) is principal variable which determines regime discharge will be in. When q95 greater than 4.0 for standard-shaped almost always EDA, while when it less 3.5, ELMfree. New edge...