A5041337691- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Solar and Space Plasma Dynamics
- Plasma Diagnostics and Applications
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Nuclear reactor physics and engineering
- Fluid Dynamics and Turbulent Flows
- Meteorological Phenomena and Simulations
- Radiation Detection and Scintillator Technologies
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Vacuum and Plasma Arcs
- Gas Dynamics and Kinetic Theory
- Dust and Plasma Wave Phenomena
- Nuclear physics research studies
- Plasma Applications and Diagnostics
- Ion-surface interactions and analysis
- Laser Design and Applications
- Advanced Data Storage Technologies
- Physics of Superconductivity and Magnetism
Princeton Plasma Physics Laboratory
2015-2024
Lodestar Research Corporation (United States)
2016-2021
Princeton University
2004-2020
Lawrence Livermore National Laboratory
2001-2020
Centre National de la Recherche Scientifique
2018
Université de Toulouse
2018
Massachusetts Institute of Technology
1997-2013
University of Colorado Boulder
2006-2010
University of Warwick
2010
University of California, San Diego
2006-2007
This is a review of what known about fluctuations and anomalous transport processes in tokamaks. It mostly considers experimental results obtained after, not included in, the reviews Liewer [Nucl. Fusion 25, 543 (1985)], Robinson [in Turbulence Anomalous Transport Magnetized Plasmas (Ecole Polytechnique, Palaiseau, France, 1986), p. 21], Surko 93]. Therefore much pioneering work field covered. Emphasis placed on where comparisons between properties have been attempted, particularly from...
A blob-filament (or simply “blob”) is a magnetic-field-aligned plasma structure which considerably denser than the surrounding background and highly localized in directions perpendicular to equilibrium magnetic field B. In experiments simulations, these intermittent filaments are often formed near boundary between open closed lines, seem arise theory from saturation process for dominant edge instabilities turbulence. Blobs become charge-polarized under action of an external force causes...
"Principles of Plasma Diagnostics." Fusion Technology, 17(1), p. 214 Additional informationNotes on contributorsS. J. Zwebenresearch physicist at the Princeton Physics Laboratory.
This paper reviews measurements of edge plasma turbulence in toroidal magnetic fusion devices with an emphasis on recent results tokamaks. The dominant feature is a high level broadband density fluctuations relative amplitude δn/n ∼ 5–100%, accompanied by large potential and electron temperature fluctuations. frequency range this ∼10 kHz–1 MHz, the size scale typically ∼0.1–10 cm perpendicular to field but many metres along field, i.e. structure nearly that 2D 'filaments'. Large intermittent...
Abstract The objectives of NSTX-U research are to reinforce the advantages STs while addressing challenges. To extend confinement physics low- A , high beta plasmas lower collisionality levels, understanding transport mechanisms that set performance and pedestal profiles is being advanced through gyrokinetic simulations, reduced model development, comparison NSTX experiment, as well improved simulation RF heating. develop stable non-inductive scenarios needed for steady-state operation,...
The two-dimensional radial vs poloidal structure and motion of edge turbulence in the National Spherical Torus Experiment (NSTX) were measured using high-speed imaging visible light emission from a localized neutral gas puff. Edge images are shown analysed for Ohmic, L- H-mode plasma conditions. often show regions strong known as 'blobs', which move both poloidally radially at typical speed ≈105 cm s−1, sometimes spatially periodic features.
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 ${10}^{16}$...
The two-dimensional (2D) radial vs poloidal structure of edge turbulence in the Alcator C-Mod tokamak [I. H. Hutchinson, R. Boivin, P. T. Bonoli et al., Nucl. Fusion 41, 1391 (2001)] was measured using fast cameras and compared with three-dimensional numerical simulations plasma turbulence. main diagnostic is gas puff imaging, which visible Dα emission from a localized D2 viewed along local magnetic field line. observed fluctuations have typical scale ≈1 cm, often strong maxima (“blobs”)...
Cross-field particle transport in the scrape-off layer (SOL) of Alcator C-Mod [Phys. Plasmas 1, 1511 (1994)] can be characterized by an effective diffusivity (Deff) that increases markedly with distance from separatrix. As a consequence, recycling onto main-chamber walls is large compared to plasma flows into divertor volume. The SOL exhibits two-layer structure: Steep gradients and moderate fluctuation levels are typically found ∼5 mm region near separatrix (near SOL) where parallel...
The intermittent turbulent transport in the scrape-off-layer (SOL) of Alcator C-Mod [I.H. Hutchinson, R. Boivin, P.T. Bonoli et al., Nucl. Fusion 41, 1391 (2001)] is studied experimentally by imaging with a very high density spatial measurements. two-dimensional structure and dynamics emission from localized gas puff are observed, features (also sometimes called “filaments” or “blobs”) typically seen. characteristics turbulence their relationship to time-averaged SOL profiles discussed...
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...
Magnetic pickup loops inserted into the Macrotor tokamak have shown a broad spectrum of oscillation in ${B}_{r}$ and ${B}_{p}$ up to $f\ensuremath{\approx}100$ kHz. The high-frequency ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{B}}_{r}$ short radial poloidal correlation lengths $L<5$ cm, contrast with usual Mirnov oscillations $f\ensuremath{\approx}7$ kHz $L\ensuremath{\gg}5$ cm. observed magnitude $\frac{\ensuremath{\Sigma}|{\stackrel{\ifmmode...
Two-dimensional tokamak edge density turbulence data are examined for possible coherent or organized structure. The spatial patterns of fluctuations ñ appear to consist localized ‘‘blobs’’ relatively high low which can move irregularly both radially and poloidally through the region. However, a statistical analysis lifetime, area, direction, speed, amplitude these blobs does not as yet suggest any structure associated with beyond that be described by time-averaged correlation functions.
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...
Wall conditioning in the Tokamak Fusion Test Reactor (TFTR) [K. M. McGuire et al., Phys. Plasmas 2, 2176 (1995)] by injection of lithium pellets into plasma has resulted large improvements deuterium–tritium fusion power production (up to 10.7 MW), Lawson triple product 1021 m−3 s keV), and energy confinement time 330 ms). The maximum current for access high-performance supershots been increased from 1.9 2.7 MA, leading stable operation at stored values greater than 5 MJ. amount on limiter...
A transport code (TRANSP) is used to simulate future deuterium-tritium (DT) experiments in TFTR.The simulations are derived from 14 TFTR DD discharges, and the modelling of one supershot discussed detail indicate degree accuracy TRANSP modelling.Fusion energy yields 01 particle parameters calculated, including profiles slowing down time, average energy, AlfvBn speed frequency.Two types simulation discussed.The main emphasis on DT equivalent, where an equal mix D T substituted for initial...
Measurements of the spatial structure tokamak edge density fluctuations ñ have been made using compact probe arrays in Caltech tokamak. The results indicate that is characterized by very short auto-correlation times and cross-correlation lengths, i.e. consist small-scale 'turbulence'. space-time this turbulence consistent with several recent non-linear instability models. local electrostatic potential measured to be qualitatively similar ñ, between indicates large outward radial particle...
High-speed high-spatial-resolution data obtained by the gas puff imaging (GPI) diagnostic on National Spherical Torus Experiment [M. Ono, M.G. Bell, R.E. Bell et al. Plasma Phys. Control. Fusion 45, A335 (2003).] is analyzed and interpreted in light of recent theoretical models for electrostatic edge turbulence blob propagation. The experiment described terms regimes that predict different dependencies radial velocity convection. Using GPI data, atomic physics analysis, tracking a restricted...
Radially propagating spatiotemporal fluctuation structures are observed in the scrape-off layer of Alcator C-Mod [I. H. Hutchinson et al., Phys. Plasmas 1, (1994)] using combination electric probes, a radial array views measuring Dα emission, and two-dimensional imaging emission. For specific magnetic-field configuration probe measured plasma density potential fluctuations along same magnetic-flux tube. Calculations cross-correlation functions intensity with ion saturation current floating...
The first far-infrared laser scattering measurements from a tokamak plasma are reported. Spatially and temporally resolved power spectra of density fluctuations in the Microtor have been studied with an absolutely calibrated system which allowed measurement wide range wave numbers $k=3 \mathrm{to} 50$ ${\mathrm{cm}}^{\ensuremath{-}1}$. wave-number dependence scattered $0.6\ensuremath{\lesssim}{k}_{\ensuremath{\perp}}{\ensuremath{\rho}}_{i}\ensuremath{\lesssim}2$ was found to satisfy...
The MIT Plasma Science and Fusion Center collaborators are proposing a high-performance Advanced Divertor RF tokamak eXperiment (ADX)-a specifically designed to address critical gaps in the world fusion research programme on pathway next-step devices: nuclear science facility (FNSF), pilot plant (FPP) and/or demonstration power (DEMO). This high-field (>= 6.5 T, 1.5 MA), high density (P/S similar MW m(-2)) will test innovative divertor ideas, including an 'X-point target divertor' concept,...
Gas puff imaging (GPI) is a diagnostic of plasma turbulence which uses neutral gas at the edge to increase local visible light emission for improved space-time resolution fluctuations. This paper reviews diagnostics in magnetic fusion research, with focus on instrumentation, cross-checks, and interpretation issues. The hardware, optics, detectors are described about 10 GPI systems implemented over past ∼15 years. Comparison results other described, many common features observed. Several...
Here, the structure and motion of discrete plasma blobs (a.k.a. filaments) in edge scrape-off layer NSTX is studied for representative Ohmic H-mode discharges. Individual were tracked 2D radial versus poloidal plane using data from gas puff imaging diagnostic taken at 400 000 frames s-1. A database blob amplitude, size, ellipticity, tilt, velocity was obtained ~45 individual blobs. Empirical relationships between various properties are described, e.g. speed amplitude tilt ellipticity. The...
This tutorial describes mechanisms for separating ions in a plasma device with respect to their atomic or molecular mass practical applications. The focus here is not on isotopes of single species but rather systems much lower resolution and higher throughput. These separation include ion gyro-orbit separation, drift-orbit vacuum arc centrifugation, steady-state rotating plasmas, several other geometries. Generic physics issues are discussed such as the charge state, neutrals molecules,...
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...