A5029824426- Fusion materials and technologies
- Magnetic confinement fusion research
- Nuclear Materials and Properties
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Ion-surface interactions and analysis
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Ionosphere and magnetosphere dynamics
- Metal and Thin Film Mechanics
- Laser-induced spectroscopy and plasma
- Advanced materials and composites
- Atomic and Molecular Physics
- Diamond and Carbon-based Materials Research
- Advanced Data Storage Technologies
- Nuclear materials and radiation effects
- Muon and positron interactions and applications
- Advanced Materials Characterization Techniques
- Laser Design and Applications
- Metallurgical Processes and Thermodynamics
- Radiation Detection and Scintillator Technologies
- Advanced Chemical Physics Studies
- Atomic and Subatomic Physics Research
Sandia National Laboratories California
2007-2022
Sandia National Laboratories
1988-2018
General Atomics (United States)
1990-2017
Lawrence Livermore National Laboratory
1992-1997
Oak Ridge National Laboratory
1992
Office of Scientific and Technical Information
1989
Princeton University
1983-1989
Princeton Plasma Physics Laboratory
1983-1989
Plasma Technology (United States)
1986
Strong magnetohydrodynamic activity has been observed in PDX neutral-beam-heated discharges. It occurs for ${\ensuremath{\beta}}_{T}q>~0.045$ and is associated with a significant loss of fast ions drop neutron emission. As much as 20%-40% the beam heating power may be lost. The instability repetitive bursts oscillations \ensuremath{\le} 1 msec duration at 1-6-msec intervals. dubbed "fishbone instability" from its characteristic signature on Mirnov coils.
Deuterium gas injected into ELMing H mode divertor discharges in the DIII-D tokamak typically reduced total power at target ~2 times and peak heat flux ~3 to 5 with modest (<10%) degradation plasma energy confinement. The parameter range for investigated was: Ip=1.0-2.0 MA, q95 approximately= 2.4-6.0 input (≲20 MW. Most of this reduction occurred sudden formation a high density, highly radiating region located between outboard separatrix strike point X point. This behaviour is associated...
Following a two-year operational period the Tokamak Fusion Test Reactor (TFTR) graphite fixed bumper limiter has been examined by variety of methods. The areal density metals was mapped in situ beta backscattering. Several tiles were detail nuclear-reaction analysis, Rutherford backscattering, and proton-induced x-ray emission to measure densities deuterium impurities. Some areas found be covered deposited material several microns thick. Other where incident plasma flux is higher much...
Recent measurements of the two-dimensional (2-D) spatial profiles divertor plasma density, temperature, and emissivity in DIII-D tokamak [J. Luxon et al., Proceedings 11th International Conference on Plasma Physics Controlled Nuclear Fusion (International Atomic Energy Agency, Vienna, 1987), p. 159] under highly radiating conditions are presented. Data obtained using a Thomson scattering system other diagnostics optimized for measuring high electron densities low temperatures these detached...
Effects of annealing after/under iron (Fe) ion irradiation on deuterium (D) retention behavior in tungsten (W) were studied. The D2 TDS spectra as a function heating temperature for 0.1 dpa damaged W showed that the D was clearly decreased increased. In particular, desorption trapped by voids largely reduced at 1173 K. TEM observation indicated size dislocation loops grown, and its density above 573 After K, almost all recovered. results positron annihilation spectroscopy suggested...
Future tokamak devices are envisioned to utilize a high-Z metal divertor with tungsten as the leading candidate. However, experiments divertors have seen significant detrimental effects on plasma performance. The DIII-D presently has carbon facing surface but study effect of and its migration around vessel, two toroidal rows tiles in region were modified inserts, composed molybdenum alloy (TZM) coated tungsten. A dedicated week experimental campaign was run inserts. One row containing...
In this work, we examine how deuterium becomes trapped in plasma-exposed tungsten and forms near-surface platelet-shaped precipitates. How these bubbles nucleate grow, as well the amount of within, is crucial for interpreting experimental database. Here, use a combined experimental/theoretical approach to provide further insight into underlying physics. With Tritium Plasma Experiment, exposed series ITER-grade samples high flux D plasmas (up 1.5 × 1022 m−2 s−1) at temperatures ranging...
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...
Exposure of tungsten to low energy (<100 eV) helium plasmas at temperatures between 900–1900 K in both laboratory experiments and tokamaks has been shown cause severe nanoscale modification the near surface resulting growth tendrils. Tendril formation can lead non-sputtered erosion dust formation. Here we report on characterization a compact electron cyclotron resonance (ECR) He plasma source with an ion flux ∼2.5 × 1019 ions m−2 s−1, average fluence 3 1024 m−2, morphology changes seen...
DIII-D currently operates with a single- or double-null open divertor and graphite walls. Active particle control cryopump has demonstrated density control, efficient helium exhaust, reduction of the inventory particles in wall. Gas puffing D2 impurities peak heat flux by factors 3-5 radiation. A combination active cryopumping feedback-controlled gas produced similar control. Experiments neon have shown that radiation is equally-divided between localized zone near X-point mantle around...