A5056706281- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Solar and Space Plasma Dynamics
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Astro and Planetary Science
- Superconducting Materials and Applications
- Nuclear Materials and Properties
- Nuclear Physics and Applications
- Electron and X-Ray Spectroscopy Techniques
- Spacecraft and Cryogenic Technologies
- Metal and Thin Film Mechanics
- Advancements in Photolithography Techniques
- Non-Destructive Testing Techniques
- Vacuum and Plasma Arcs
- Quantum, superfluid, helium dynamics
- Space Exploration and Technology
- Electromagnetic Launch and Propulsion Technology
- Dust and Plasma Wave Phenomena
- Silicon and Solar Cell Technologies
- Additive Manufacturing Materials and Processes
- Injection Molding Process and Properties
- Semiconductor Quantum Structures and Devices
Oak Ridge National Laboratory
2024
University of Wisconsin–Madison
2011-2024
General Atomics (United States)
2019
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2011
CEA Cadarache
2011
University of Stuttgart
2011
Middlebury College
2006
Argonne National Laboratory
2005
Helicon current drive (CD), also called fast wave CD in the lower hybrid range of frequencies, has long been regarded as a promising tool for reactor grade plasmas.A newly installed MW-level system at DIII-D will be first test this technology reactor-relevant plasmas, sense that full single-pass absorption is expected.A 30-module traveling antenna and optimized in-vessel early 2020.The linear electromagnetic characteristics unloaded module array have extensively tested both on bench vessel...
Abstract A major challenge facing the design and operation of next-step high-power steady-state fusion devices is to develop a viable divertor solution with order-of-magnitude increases in power handling capability relative present experience, while having acceptable target plate erosion being compatible maintaining good core plasma confinement. new initiative has been launched on DIII-D scientific basis for design, installation, an advanced evaluate boundary solutions applicable next step...
Abstract An efficient removal of He ash by active pumping in future fusion devices is necessary to avoid fuel dilution and not degrade the core confinement properties. Therefore, a deep understanding underlying physics mechanisms mandatory. Helium exhaust has been experimentally investigated at ASDEX Upgrade tokamak. This an ideal test environment, thanks ITER-like divertor geometry, extensive diagnostics coverage presence plasma-facing components made tungsten. The efficiency, characterized...
Peeling modes are observed at the plasma edge in Pegasus Toroidal Experiment under conditions of high current density (Jedge ~ 0.1 MA m−2) and low magnetic field (B T) present near-unity aspect ratio. Their macroscopic properties measured using external Mirnov coil arrays, Langmuir probes high-speed visible imaging. The modest parameters short pulse lengths discharges permit direct measurement internal structure with an insertable array Hall-effect sensors, providing profile its temporal...
Experiments to combine a radiating divertor or mantle with high power, βN plasma operation have successfully reduced the heat flux by 40% but also encountered several challenging problems. For example, injecting either neon argon seed impurities led both significant fuel dilution of core and emergence harmful tearing mode activity which compromised beta energy confinement time. Increased closure resulted in more effective control over injected impurity inventory, although it was observed...
Abstract Erosion patterns in a 3D magnetic topology are significantly altered when compared to an axisymmetric scenario due differences the impurity transport plasma environment. When resonant perturbations applied L-Mode discharges, eroded impurities can buildup regions where would otherwise lead zones of net erosion across full toroidal length divertor. The reduction on local and integrated observed parametric study anomalous diffusion content plasma, extension divertor lifetimes low power...
An impedance model is formulated and tested for the ∼1 kV, 1 kA/cm2, arc-plasma cathode electron source used local helicity injection tokamak startup. A double layer sheath established between high-density arc plasma (narc≈1021 m−3) within source, less dense external edge (nedge≈1018 into which current injected at applied injector voltage, Vinj. Experiments on Pegasus spherical show that current, Iinj, increases with Vinj according to standard scaling Iinj∼Vinj3/2 low transitions...
The ordinary–extraordinary (O–X) mode conversion is modeled with the aid of a 2D full-wave code in Pegasus toroidal experiment as function launch angles. It shown how shape plasma density profile front antenna can significantly influence efficiency and, thus, generation electron Bernstein waves (EBWs). therefore desirable to control for successful operation an EBW heating and current drive system. On other hand, be resilient vertical displacements large ±10 cm.
In extreme ultraviolet lithography (EUVL) environments both laser produced plasma (LPP) and gas discharge (GDPP) configurations face serious issues regarding components lifetime performance under particle bombardment, in particular collector mirrors. For debris, fast ions, neutrals, condensable EUV radiator fuels (Li, Sn) can affect addition, mirrors are exposed to impurities (H,C,O,N), off-band radiation (depositing heat) highly-charged ions leading their degradation consequently limiting...
EUV metallic light radiators such as Sn or Li used for lithography will limit the lifetime of collector optics in source devices by both contamination and irradiation. Generation requires use hot, dense plasma. Pinch dynamics generates fast ions atoms, sources (Sn, Li) with energies ranging from 100 eV up to several keV. The expanding plasma thermalize condense nearby components, including debris shield optics. incident distribution onto likely include ions. lead two different mechanisms....
Effective helium confinement time, τp*,He, and its ratio with energy τp*,He/τE, are key metrics quantifying the suitability of fusion plasmas for a continuous burn. Comparisons in DIII-D tokamak discharges suppression edge localized modes (ELMs) by resonant magnetic field perturbations (RMPs) to corresponding unperturbed ELMy found that both these were strongly reduced, factor approximately 2, after application RMPs. This reduction τp*,He during RMP ELM was observed plasma core, edge,...
Actively enhancing plasma radiated power has been used to reduce divertor heat flux in high power, high-performance double null (DND) and near-DND plasmas DIII-D, while at the same time maintaining acceptable energy confinement. One form of this approach that we focus on here is radiating mantle. The effectiveness mantle was found depend strongly location electron cyclotron (EC) heating deposition effect seed impurities have triggering inimical MHD activity inside plasma. In addition,...
Abstract The suppression of edge-localized modes (ELMs) by applying resonant magnetic perturbations (RMPs) is well studied in low collisionality deuterium plasmas as a measure to reduce transient divertor heat loads. However, ELM has yet be demonstrated non-nuclear fuels such hydrogen and + helium mixtures which are the main ion species used ITER pre-fusion power operation (PFPO) phase. For first time, attempts have been made access with RMPs ITER-like at DIII-D ASDEX Upgrade. experiments...