A5058944932- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Building Energy and Comfort Optimization
- Urban Heat Island Mitigation
- Hygrothermal properties of building materials
- Solar and Space Plasma Dynamics
- Laser-induced spectroscopy and plasma
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Semiconductor materials and devices
- Silicon Carbide Semiconductor Technologies
- Advanced Data Storage Technologies
- Pulsars and Gravitational Waves Research
- Metal and Thin Film Mechanics
- Nuclear Materials and Properties
- Electrostatic Discharge in Electronics
- Geophysics and Gravity Measurements
- Diamond and Carbon-based Materials Research
- Gas Dynamics and Kinetic Theory
- Facilities and Workplace Management
General Atomics (United States)
2011-2023
University of California, Los Angeles
2004-2010
Pennsylvania State University
2008-2009
University of Toronto
2009
University of California, San Diego
2009
Oak Ridge National Laboratory
1992-2008
Advanced Fiber Technologies (United States)
2008
Fusion Academy
2002
Fusion (United States)
1999-2002
Lawrence Livermore National Laboratory
1995-2001
We report the results of first experiments on DIII-D tokamak to examine dependence transport and stability characteristics ITER hybrid scenario plasmas toroidal flow (or rotation) plasma. With new capability independently vary neutral beam torque power, central rotation has been reduced by as much a factor 4.6 compared with discharges unidirectional beams. Although energy confinement decreases m/n = 3/2 NTM amplitude increases for low speed, fusion performance figure merit, , still exceeds...
AbstractTo move to a fusion DEMO power plant after ITER, Fusion Nuclear Science Facility (FNSF) is needed in addition ITER and research operating tokamaks those under construction. The FNSF will enable on how utilize deal with the products of reactions, addressing such issues as extract energy from neutrons alpha particles into high-temperature process heat streams be either used directly or converted electricity, make tritium lithium, effects blanket structures, manage first wall surface...
Abstract The ‘Super H-Mode’ regime is predicted to enable pedestal height and fusion performance substantially higher than standard H-Mode operation. This exists due a bifurcation of the pressure, as function density, that by EPED model occur in strongly shaped plasmas above critical density. Experiments on Alcator C-Mod DIII-D have achieved access Super (and Near H) regime, obtained very high including highest tokamak ( p ped ~ 80 kPa) experiments operating near ITER magnetic field. H...
The energy lost from the pedestal region due to an average ELM in DIII-D is determined changes electron density and temperature profiles as measured by Thomson scattering. loss of associated with conduction found decrease increasing density. density, or convective transport, remains constant a function scaling two transport channels, convection, are examined terms parallel processes scrape-off-layer divertor.
Abstract A total power injection up to 0.3 GJ has been achieved in EAST long pulse H-mode operation of 101.2 s with an ITER-like water-cooled tungsten (W) mono-block divertor, which steady-state exhaust capability 10 MWm −2 . The peak temperature W target saturated at 12 the value T ~ 500 °C a heat flux ~3.3 MW m being maintained during discharge. By tailoring 3D divertor plasma footprint through edge magnetic topology change, load was broadly dispersed and thus sputtering were well...
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...
Since its inception in 2002, the International Tokamak Physics Activity topical group on Integrated Operational Scenarios (IOS) has coordinated experimental and modelling activity development of advanced inductive scenarios for applications ITER tokamak. The physics basis prospects have been significantly during that time, especially with respect to results. principal findings this research are as follows. Inductive capable higher normalized pressure (βN ⩾ 2.4) than baseline scenario = 1.8)...
We review progress made on the advanced tokamak path to fusion energy by DIII-D National Fusion Facility (Luxon et al. in Nucl 42:614, 2002). The represents a highly attractive approach for future steady state power plant. In this concept, there is natural alignment between high pressure operation, favorable stability and transport properties, self-driven ('bootstrap') plasma current sustain operation efficiently without disruptions. Research has identified several promising configurations...
A series of observations is presented concerning divertor heat flux, qdiv, in the DIII-D tokamak, and it shown that many features can be accounted for by assuming flux flows preferentially along field lines because τ|| < τ⊥ scrape-off layer (SOL). Exceptions to this agreement are pointed out discrepancies explained means two dimensional (2-D) effects. About 80% discharge input power for. The deposited on target plate due enhanced losses during edge localized modes (ELMs) less than 10% total...
The DIII-D Advanced Tokamak (AT) program in the tokamak [J. L. Luxon, Plasma Physics and Controlled Fusion Research, 1986, Vol. I (International Atomic Energy Agency, Vienna, 1987), p. 159] is aimed at developing a scientific basis for steady-state, high-performance operation future devices. This requires simultaneously achieving 100% noninductive with high self-driven bootstrap current fraction toroidal beta. Recent progress this area includes demonstration of conditions beta, βT=3.6%,...
Recent studies on the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] have elucidated key aspects of dependence stability, confinement, and density control plasma magnetic configuration, leading to demonstration nearly noninductive operation for &gt;1 s with pressure 30% above ideal no-wall stability limit. Achieving fully requires high pressure, good through divertor pumping. Plasma geometry affects all these. Ideal magnetohydrodynamics modeling external kink suggests that it...
The objective of the Fusion Development Facility (FDF) under consideration is to carry forward advanced tokamak physics for optimization fusion reactors and enable development fusion's energy applications. A concept FDF based on approach with conservative expressions nonsuperconducting magnet technology presented. It envisioned nominally provide 2 MW/m2 neutron wall loading operate continuously up weeks as required nuclear component research development. will have tritium breeding capability...
The DIII-D programme has recently initiated an effort to provide suitably scaled experimental evaluations of four primary ITER operational scenarios. New and unique features this work are that the plasmas incorporate essential scenarios anticipated operating characteristics; e.g. plasma cross-section, aspect ratio value I/aB discharges match design, with size reduced by a factor 3.7. Key aspects all scenarios, such as target values for βN H98, have been replicated successfully on DIII-D,...
The radiative dissipation of divertor target heat flux on DIII-D is shown to greatly exceed the limitations energy transport dominated by electron thermal conduction parallel magnetic field. More than 80% power flowing into outboard dissipated through radiation with a broad poloidal profile. It that convection over large region consistent data.
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...
Densities of up to 40% above the Greenwald limit are reproducibly achieved in high confinement (HITER89P = 2) ELMing H mode discharges. Simultaneous gas fuelling and divertor pumping were used obtain these results. Confinement discharges, similar moderate density mode, is characterized by a stiff temperature profile, therefore sensitive profile. A particle transport model presented that explains roles geometry for access densities. The energy loss per ELM at factor five lower than...
The reduction in size of Type I edge localized modes (ELMs) with increasing density is explored DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] for the purpose studying underlying transport ELM energy. separate convective and conductive energy due to an determined by Thomson scattering measurements electron temperature pedestal. from pedestal during decreases density, while remains nearly constant. scaling loss compared stability model. role divertor sheath limiting explored. Evidence...
Results from a series of dedicated experiments measuring the effect particle and energy pulses Type-I edge localized modes (ELMs) in DIII-D scrape-off layer (SOL) divertor are compared with simple model ELM propagation boundary plasma. The asserts that perturbations is dominated by ion parallel convection along SOL field lines recovery perturbation determined recycling physics. Timescales associated initial changes plasma parameters expected to be on order transit time outer midplane, where...
A plasma initiation and current ramp up scenario envisioned for ITER has been simulated in DIII-D experiments. These discharges were limited on the low field side (LFS) during initial up, as specified baseline startup scenario. Initial experiments produced internal inductance (ℓ i ), higher than design value shaping coils, often leading to vertical instabilities. modified with larger volume was developed reduce ℓ up. This large-bore scenario, also limiting LFS, a lower avoided Feedback...
‘Puff-and-pump’ radiating divertor scenarios, applied to both upper single-null (SN) and double-null (DN) H-mode plasmas, result in a 30–60% increase radiated power with little or no decrease τ E . Argon was injected into the private flux region of divertor, plasma flow enhanced by combination deuterium gas puffing upstream targets particle pumping at targets. For same constant injection rate, argon penetrated main SNs more rapidly reached higher steady-state concentration when B × ∇ -ion...
Results and interpretation of recent experiments on DIII-D designed to evaluate divertor geometries favourable for radiative heat dispersal are presented. Two approaches examined here involved lengthening the parallel connection in scrape-off layer, L||, increasing radius outer separatrix strike point, ROSP, with goal reducing target temperature, TTAR, density, nTAR. From one-dimensional (1D) two-point modelling based conducted flux, it is expected that: , where nSEP midplane density. These...
Abstract Detached radiative divertor plasmas are examined in DIII-D as a function of power. The 2D profile plasma electron density and temperature is reconstructed from Thomson data while energy transport deduced power balance measurements. combination diagnostics reveals that parallel transitions to convective flow at constant 5–10 eV Simple considerations would imply proportional for Mach 1 flow. However, the divertor, upstream separatrix core densities increase significantly less than...