A5068914560- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear Physics and Applications
- Astronomical Observations and Instrumentation
- Plasma Diagnostics and Applications
- Nuclear reactor physics and engineering
- Spacecraft and Cryogenic Technologies
- Astronomy and Astrophysical Research
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Materials and Properties
- Solar and Space Plasma Dynamics
- Spacecraft Design and Technology
- Particle Accelerators and Free-Electron Lasers
- Astro and Planetary Science
- Atomic and Subatomic Physics Research
- Gyrotron and Vacuum Electronics Research
- Space Exploration and Technology
- Advanced Data Storage Technologies
- Nuclear Engineering Thermal-Hydraulics
- Stellar, planetary, and galactic studies
- Nuclear physics research studies
Princeton Plasma Physics Laboratory
2014-2024
National Institute for Fusion Science
2016-2018
The Graduate University for Advanced Studies, SOKENDAI
2018
Auburn University
2018
University of Maryland, College Park
2018
Oak Ridge National Laboratory
1992-2016
Max Planck Society
2016
Max Planck Institute for Plasma Physics - Greifswald
2016
Australian National University
2016
Physikalisch-Technische Bundesanstalt
2016
While the results of early work on density limit in tokamaks from ORMAK and DITE groups have been useful over years, recent experiments requirements for extrapolation to future prompted a new look at this subject. There are many physical processes which attainable densities tokamak plasmas. These include: (1) radiation low Z impurities, convection, charge exchange other losses plasma edge; (2) or high impurities core; (3) deterioration particle confinement (4) inadequate fuelling, often...
The problem of control the vertical instability is studied for a massless filamentary plasma with finite resistivity included shell and active coil. Stability boundaries are determined. system can be stabilized up to critical decay index, which predominantly function geometry passive stabilizing shell. A second, smaller, coils, determines limit stability in absence derivative gain circuit. also numerically order incorporate non-linear effects power supply dynamics. bandwidth requirement...
A method for determining plasma shape and global properties of high-beta non-circular tokamak equilibria (βp, β, q ℓi) from magnetic sensor data is described. The technique uses a least-squares fitting procedure to find the boundary force balance analysis (as opposed complete solution MHD equilibrium equation) determine pressure. Estimates uncertainties in computed quantities are also obtained, fast enough that it can be used provide time history (up 100 points) ISX-B discharges within two...
A Korean fusion energy development promotion law (FEDPL) was enacted in 2007. As a following step, conceptual design study for steady-state demonstration reactor (K-DEMO) initiated 2012. After the thorough 0D system analysis, parameters of main machine characterized by major and minor radii 6.8 2.1 m, respectively, were chosen further study. The analyses heating current drives performed plasma operation scenarios. Preliminary results on lower hybrid neutral beam drive are included herein....
Compact optimized stellarators offer novel solutions for confining high-β plasmas and developing magnetic confinement fusion. The three-dimensional plasma shape can be designed to enhance the magnetohydrodynamic (MHD) stability without feedback or nearby conducting structures provide drift-orbit similar tokamaks. These configurations possibility of combining steady-state low-recirculating power, external control, disruption resilience previous with low aspect ratio, high β limit, good...
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...
The proposed Fusion Nuclear Science Facility (FNSF) represents the first facility to enter complex fusion nuclear regime, and its technical mission attributes are being developed. FNSF one part of energy development pathway commercial power plant with other major components pre-FNSF research development, in parallel FNSF, pre-DEMO demonstration (DEMO). Energy Systems Studies group is developing basis for order provide a better understanding demands on plasma science programs.
Recent calculations have shown that when external momentum sources and plasma rotation are included in the neoclassical theory, standard results for impurity transport can be strongly altered. Under appropriate conditions, inward convection is reduced by co-injection enhanced counter-injection. In order to examine theoretical predictions, several observations of been made ISX-B tokamak during neutral-beam injection comparison with seen Ohmic heating alone. Both intrinsic contaminants...
Confinement studies on the Impurity Study Experiment (ISX-B) in beam-heated plasmas contaminated with small quantities of low-Z impurities are reported. Experimental results correlation particle and energy confinement presented. A linear relationship plasma density is observed. As increased further, this effect saturates becomes independent electron density. The experiments have been extended to higher beam power, resulting an expansion ISX-B operating space. Impurities other than neon...
The results from the investigation of neoclassical core transport and role radial electric field profile (Er) in first operational phase Wendelstein 7-X (W7-X) stellarator are presented. In plasmas, details Er expected to have a strong effect on both particle heat fluxes. Investigation is important understanding validation calculations. closely related perpendicular plasma flow (u⊥) through force balance equation. This allows be inferred measurements velocity, which can measured using x-ray...
High-speed pellet fuelling experiments have been performed on the ISX-B device in a new regime characterized by large global density rise both Ohmically and neutral-beam heated discharges. Hydrogen pellets of 1 mm diameter were injected plasma midplane at velocities exceeding km·s−1. In low-temperature Ohmic discharges, penetrate beyond magnetic axis, such cases sharp decrease ablation is observed as passes centre. This behaviour can be accounted for an model that includes dynamic cooling...
Neutral-beam injection of up to 2.5 MW into plasmas in the ISX-B tokamak (R0 = 0.93 m, a 0.27 BT 0.9–1.5 T, Ip 70–210 kA, e 2.5–10×1013 cm−3) has created with volume-averaged beta ∼ 2.5%, peak values 9%, and root-mean-square 3.5%. Energy confinement time is observed decrease by about factor two as beam power goes from 0 MW; caused predominantly electron falling below predictions 'Alcator scaling' 3–4 at high power. An empirical relationship form fits our measurements over wide range plasma...
The external inductance of an axisymmetric toroidal plasma with arbitrary aspect ratio and cross section is obtained using a Green’s function method. By varying equivalent skin current density over the surface, while keeping total fixed, boundary made to coincide magnetic surface. Numerical computations self-inductance mutual as functions elongation are fitted simple analytic formulas. effect distributed on volt-seconds required reach prescribed net considered.
Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters December 2015. At end of 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were operation, allowing detailed studies many interesting plasma phenomena. For example, fast neutral gas manometers supported video cameras (including one fast-frame camera frame rates...
Liquid metal (LM) plasma-facing components (PFCs) may provide a resolution to the challenging fusion environment, particularly first wall and divertor surfaces. Transforming these concepts into viable technologies will require considerable research development. With nuclear regime in mind, Fusion Energy System Studies group examined LM PFCs order identify needed thrusts that could accelerate their development assess viability. behavior, solid substrate aspects, facility integration aspects...
Gross-energy-confinement times (${\ensuremath{\tau}}_{E}$) in the ISX-$A$ (Impurity Study Experiment) tokamak exceeded predictions of usual empirical scaling relations. We attribute this performance to reductions impurity radiation and magnetohydrodynamically driven loss channels. The value ${\ensuremath{\tau}}_{E}$ reached a limit as function plasma density. suggest that is due transition from electron- ion-dominated regimes. Maximum attainable values increased with discharge current,...
Access to the MHD second stability regime has been achieved in ATF torsatron. Experimental \ensuremath{\beta} values (${\ensuremath{\beta}}_{0}$\ensuremath{\le}3%, with fast ions contributing \ensuremath{\approxeq}(1/3 of pressure at high \ensuremath{\beta}) are well above theoretical transition value (${\ensuremath{\beta}}_{c}$\ensuremath{\approxeq}1.3% for ideal modes) required reach this regime. The relatively low ${\ensuremath{\beta}}_{c}$ results from operation peaked profiles. measured...
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...
Key physics issues in the design of a high- quasi-axisymmetric stellarator configuration are discussed. The goal study is compact with aspect ratio comparable to that tokamaks and good transport stability properties. Quasi-axisymmetry has been used provide drift trajectories. Ballooning stabilization accomplished by strong axisymmetric shaping, yielding whose core second regime for ballooning modes. A combination externally generated shear non-axisymmetric corrugation plasma boundary...
High-beta, low-aspect-ratio (“compact”) stellarators are promising solutions to the problem of developing a magnetic plasma configuration for fusion power plants that can be sustained in steady state without disrupting. These concepts combine features and advanced tokamaks have aspect ratios similar those (2–4). They based on computed configurations shaped three dimensions provide desired stability transport properties. Experiments planned as part program develop this concept. A β=4%...