A5067219154- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Physics of Superconductivity and Magnetism
- Nuclear reactor physics and engineering
- Solar and Space Plasma Dynamics
- Advanced Data Storage Technologies
- Semiconductor materials and devices
- Metal and Thin Film Mechanics
- Magnetic properties of thin films
- Electronic and Structural Properties of Oxides
- Semiconductor Quantum Structures and Devices
- Dust and Plasma Wave Phenomena
- GaN-based semiconductor devices and materials
- Ion-surface interactions and analysis
- Nuclear Physics and Applications
- Radio Frequency Integrated Circuit Design
- Scientific Computing and Data Management
- Copper Interconnects and Reliability
- Atomic and Subatomic Physics Research
- Atomic and Molecular Physics
Princeton Plasma Physics Laboratory
2015-2024
Princeton University
2014-2024
Atacama Large Millimeter Submillimeter Array
2023-2024
Fusion (United States)
1980-2021
Max Planck Institute for Plasma Physics
2014-2021
Max Planck Institute for Plasma Physics - Greifswald
2021
Culham Science Centre
2021
Plasma Technology (United States)
2021
Fusion Academy
2021
ITER
2021
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,...
A genetic algorithm (GA) is proposed to optimise train movements using appropriate coast control that can be integrated within automatic operation (ATO) systems. The output for a changes with the interstation distances and gradient profiles, current operating conditions of mass rapid transit (MRT) system, namely, (i) schedules, (ii) expected passenger loads (iii) track voltages. generates an optimum based on evaluation punctuality, riding comfort energy consumption. Before sets off...
2000 Å as-deposited high Tc superconducting Y1Ba2Cu3O7−x films with zero-resistance temperatures of ∼89 K and critical current densities about 0.7×106 A/cm2 at 77 have been reproducibly fabricated a substrate holder temperature 650 °C, using pulsed laser deposition, no post-annealing. One key to these results is the injection gaseous oxygen into laser-produced plume just in front target. In this way, correct amount incorporated as-grown film so that post-deposition treatment becomes...
Thin superconducting films of Y-Ba-Cu-O were prepared at 650 °C using the pulsed laser deposition technique. The as-deposited fully low temperature (30 K). After annealing in oxygen 450 for 3 h, exhibited superconductivity with zero resistance temperatures as high 83 K. Film-substrate interface reaction was minimal revealed by Rutherford backscattering and Auger electron spectrometry. These processed such are also found to have excellent planar surface morphology critical current density.
Thin films of Y-Ba-Cu-O superconductors on (100) SrTiO3 were prepared using the pulsed excimer laser evaporation technique. After an annealing treatment in oxygen exhibited superconductivity with zero resistance at 85 K transition widths (90%–10%) as narrow a 2 K. A considerable amount orientation respect to substrates was observed by x-ray diffraction and ion channeling techniques. Interface reaction revealed Rutherford backscattering Auger electron spectrometry resulted thickness...
An atmospheric pressure plasma source operated by radio frequency power has been developed. This produces a unique discharge that is volumetric and homogeneous at with gas temperature below 300 °C. It also large quantity of oxygen atoms, ∼5×1015 cm−3, which important value for materials applications. A theoretical model shows electron densities 0.2–2×1011 cm−3 characteristic energies 2–4 eV helium discharges level 3–30 W cm−3.
We have grown ultrathin films of Y1Ba2Cu3O7−x in situ on (001) SrTiO3 by pulsed laser deposition. The zero resistance transition temperature (Tc0) is >90 K for >300 Å thick. critical current density (Jc at 77 K) 0.8×106 A/cm2 a 300 film and 4–5×106 1000 film. Tc0 Jc deteriorate rapidly below Å, reaching values 82 K, respectively, 100 Films only 50 thick exhibit metallic behavior possible evidence superconductivity without showing to 10 K. These results are understood the basis...
By considering the effect of finite aspect ratio, neoclassical ion thermal conductivity has been found to be significantly larger than reported by Hazeltine, Hinton, and Rosenbluth. A simple correction expression Hinton Hazeltine is suggested.
The Korea Superconducting Tokamak Advanced Research (KSTAR) project is the major effort of national fusion programme Republic Korea. Its aim to develop a steady state capable advanced superconducting tokamak establish scientific and technological basis for an attractive reactor. parameters are: radius 1.8 m, minor 0.5 toroidal field 3.5 T plasma current 2 MA, with strongly shaped cross-section double null divertor. initial pulse length provided by poloidal magnet system 20 s, but can be...
Global electrostatic ITG turbulence physics, together with background dynamics, has been simulated in a realistic tokamak core geometry using XGC1, full-function 5D gyrokinetic particle code. An adiabatic electron model used. Some verification exercises of XGC1 have presented. The simulation volume extends from the magnetic axis to pedestal top inside separatrix. Central heating is applied, and number, momentum energy conserving linearized Monte Carlo Coulomb collision In turbulent region,...
The fundamental properties of steep neoclassical plasma pedestals in a quiescent tokamak have been investigated with new guiding center particle code XGC: an X-point included Guiding Center code. It is shown that the width steepest similar to experimentally observed edge pedestal width, and must be accompanied by self-consistent negative radial electric field well. also can form naturally at diverted as source from neutral penetration (and heat flux core plasma) balanced sharply increasing...
Etching of Y-Ba-Cu-O superconducting thin films has been accomplished using a pulsed excimer laser (248 nm, 30 ns). Etch depth as function the number pulses was linear over wide range incident energy densities. An etch threshold density 0.11 J/cm2 observed and rate per pulse scaled linearly with logarithm density. The dependence is adequately explained by absorption model an inverse length 2.3×105 cm−1.
By depositing YBaCuO films at low substrate holder temperatures (600 °C) using a pulsed laser, with the orthorhombic phase exhibiting superconductivity high zero resistance (Tc0) were produced. Tc0 values as 50 and 80 K seen on deposited directly Si only nm ZrO2 buffer layer, respectively. The key to successful film deposition is processing involved, which minimized interface reactions observed by Auger electron spectrometry.
A systematic, constructive and self-consistent procedure to quantify nonlocal, nondiffusive action at a distance in plasma turbulence is exposed applied turbulent heat fluxes computed from the state-of-the-art full-$f$, flux-driven gyrokinetic GYSELA XGC1 codes. striking commonality found: transport below dynamically selected mesoscale has structure of L\'evy distribution, strongly nondiffusive, scale-free, avalanche mediated; larger scales, we report observation self-organized flow which...
The XGC1 edge gyrokinetic code is used for a high fidelity prediction the width of heat-flux to divertor plates in attached plasma condition. simulation results are validated against empirical scaling $\lambda_q \propto B_P^{-\gamma}$ obtained from present tokamak devices, where $\lambda_q$ mapped outboard midplane and $\gamma_q=1.19$ as defined by T. Eich et al. [Nucl. Fusion 53 (2013) 093031], $B_P$ magnitude poloidal magnetic field at separatrix surface. This predicts \leq 1mm$ when...
An overview of the physics intrinsic torque is presented, with special emphasis on phenomenology toroidal rotation in tokamaks, its theoretical understanding, and variety momentum transport bifurcation dynamics.Ohmic reversals ECH-driven counter are discussed some detail.Symmetry breaking by LSN vs. USN asymmetry related to origin at separatrix.
A fast edge turbulence suppression event has been simulated in the electrostatic version of gyrokinetic particle-in-cell code XGC1 a realistic diverted tokamak geometry under neutral particle recycling. The results show that sequence turbulent Reynolds stress followed by neoclassical ion orbit-loss driven together conspire to form sustaining radial electric field shear and quench transport just inside last closed magnetic flux surface. main action is located thin layer around ψN≃0.96–0.98,...
Data-driven science and technology offer transformative tools methods to science. This review article highlights the latest development progress in interdisciplinary field of data-driven plasma (DDPS), i.e., whose is driven strongly by data analyses. Plasma considered be most ubiquitous form observable matter universe. Data associated with plasmas can, therefore, cover extremely large spatial temporal scales, often provide essential information for other scientific disciplines. Thanks...
The extensive design effort for KSTAR has been focused on two major aspects of the project mission - steady-state-operation capability and advanced tokamak physics. steady state aspect is reflected in choice superconducting magnets, provision actively cooled in-vessel components, long pulse current drive heating systems. incorporated features associated with flexible plasma shaping, double null divertor passive stabilizers, internal control coils a comprehensive set diagnostics. Substantial...
The effect of finite-aspect ratio on the impurity contribution to neoclassical ion thermal conductivity is studied. A simple modification pure-ion case obtained with assumption that single heavy species in Pfirsch–Schlüter regime. It found larger than usual approximation: Zeff times pure conductivity.
One problem with the growth of high quality c-axis oriented YBa2Cu3O7−x films is tendency film surface to become rough. We studied mechanism as a function deposition rate using pulsed laser deposition. These form by classic nucleation and process; thickness at which nucleated islands coalesce increased decreasing rate. The has pinholes prior coalescence nucleates outgrowths during coalescence. enlarge rapidly because they contain materials crystallographic directions rates faster than that...
The pulsed laser thin-film deposition process can enable preparation of thin films complex composition with good control over the film stoichiometry. compositions are similar to that target pellet and as a consequence this technique appears be an ideal method for preparing high Tc on variety substrates.The factors which contribute beneficial phenomenon have been explored by ionization mass spectrometry (LIMS) post ablation (PAI) neutral velocity analysis in order determine velocities ejected...
High oxygen partial pressure has been found to be an important parameter for the pulsed laser deposition of as-deposited superconducting thin films with high Tc and Jc. The optical emissions from both elemental oxide species ejected target YBa2Cu3O7−x during process increase pressure, emission showing a stronger dependence than emission. dynamics interaction between atoms in laser-produced plume were studied by wavelength time-resolved measurement. results are qualitatively explained using...
Superconducting thin films of Y1Ba2Cu3Ox with superconducting transition temperature (Tc) near 90 K have been prepared by a laser deposition technique. We show that on sapphire, lithium niobate, and strontium titanate under identical processing conditions exhibit different electrical characteristics. The film surfaces, interfaces, crystallinity studied number analytical techniques. conclude the substrate influences properties primarily in three ways: thermal expansion mismatch introduces...