A5018443646- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Particle Detector Development and Performance
- Electrostatic Discharge in Electronics
- Particle Accelerators and Free-Electron Lasers
- Laser-Matter Interactions and Applications
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Cold Fusion and Nuclear Reactions
- Advanced Data Storage Technologies
- Radiation Detection and Scintillator Technologies
- Pulsed Power Technology Applications
- Nuclear reactor physics and engineering
- Ion-surface interactions and analysis
- Radiation Effects in Electronics
- Gyrotron and Vacuum Electronics Research
- Electromagnetic Compatibility and Noise Suppression
Magneto-Inertial Fusion Technologies (United States)
2017-2025
University of Rochester
2006-2024
University of California, Irvine
2006-2016
Tri Alpha Energy (United States)
2010-2013
Princeton Plasma Physics Laboratory
1994-2009
General Atomics (United States)
2006-2009
Princeton University
1994-2006
Higashihiroshima Medical Center
2006
Hiroshima University
2006
Lawrence Livermore National Laboratory
2006
Abstract A code that models signals produced by charge-exchange reactions between fast ions and injected neutral beams in tokamak plasmas is described. With the fast-ion distribution function as input, predicts efflux to a particle analyzer (NPA) diagnostic photon radiance of Balmer-alpha light D α (FIDA) diagnostic. Reactions with both primary neutrals cloud secondary “halo” surround beam are treated. Accurate calculation fraction occupy excited atomic states (the collisional-radiative...
Hydrogenic fast-ion populations are common in toroidal magnetic fusion devices, especially devices with neutral beam injection. As the fast ions orbit around device and pass through a beam, some neutralize emit Balmer-alpha light. The intensity of this emission is weak compared signals from injected neutrals, warm (halo) neutrals cold edge but, for favourable viewing geometry, Doppler shifted away these bright interfering signals. Signals detected DIII-D tokamak. When electron density...
A hot stable field-reversed configuration (FRC) has been produced in the C-2 experiment by colliding and merging two high-β plasmoids preformed dynamic version of θ-pinch technology. The process exhibits highest poloidal flux amplification obtained a magnetic confinement system (over tenfold increase). Most kinetic energy is converted into thermal with total temperature (T{i}+T{e}) exceeding 0.5 keV. final FRC state record lifetime approaching classical values. These findings should have...
Combined neutral beam injection and fast wave heating at the fourth fifth cyclotron harmonics accelerate ions in DIII-D tokamak. Measurements with a nine-channel fast-ion D-alpha (FIDA) diagnostic indicate formation of tail above energy. Tail correlates enhancement d–d neutron rate value that is expected absence fast-wave acceleration. FIDA spatial profiles pressure inferred from equilibrium both acceleration near magnetic axis for centrally located resonance layer. The largest 8–10 cm...
Field reversed configurations (FRCs) with high confinement are obtained in the C-2 device by combining plasma gun edge biasing and neutral beam injection. The creates an inward radial electric field that counters usual FRC spin-up. n = 2 rotational instability is stabilized without applying quadrupole magnetic fields. FRCs nearly axisymmetric, which enables fast ion confinement. also produces E × B shear layer, may explain observed improved particle transport. times factors to 4, lifetimes...
Z-pinch platforms constitute a promising pathway to fusion energy research. Here, we present one-dimensional numerical study of the staged (SZP) concept using FLASH and MACH2 codes. We discuss verification codes two analytical benchmarks that include Z-pinch-relevant physics, building confidence on codes' ability model such experiments. Then, is used simulate different SZP configurations: xenon gas-puff liner (SZP1*) silver solid (SZP2). The SZP2 results are compared against previously...
Magnetically driven implosions involving a liner collapsing onto target are inherently vulnerable to the magneto-Rayleigh–Taylor instability (MRTI). Among various approaches proposed achieve fusion conditions within target, staged Z-pinch (SZP) concept employs high-Z liner, advantages of which remain an active area investigation. Consequently, ongoing design optimization efforts essential, while critical physical processes such as magnetic field (B-field) diffusion and radiation transport...
The Tokamak Fusion Test Reactor (TFTR) (R. J. Hawryluk, to be published in Rev. Mod. Phys.) experiments on high-temperature plasmas, that culminated the study of deuterium–tritium D–T plasmas containing significant populations energetic alpha particles, spanned over two decades from conception completion. During design TFTR, key physics issues were magnetohydrodynamic (MHD) equilibrium and stability, plasma energy transport, impurity effects, reactivity. Energetic particle was given less...
An instability with a lower frequency than the toroidicity-induced Alfvén eigenmode was initially identified as beta-induced (BAE). Instabilities characteristic spectral features of this “BAE” are observed in wide variety tokamak plasmas, including plasmas negative magnetic shear. These modes destabilized by circulating beam ions and they transport from plasma core. The scalings these “BAEs” compared to theoretical predictions for modes, kinetic ballooning ion thermal velocity energetic...
Fast-ion transport induced by Alfvén eigenmodes (AEs) is studied in beam-heated plasmas on the National Spherical Torus Experiment [Ono et al., Nucl. Fusion 40, 557 (2000)] through space, time, and energy resolved measurements of fast-ion population. losses associated with multiple toroidicity-induced AEs (TAEs), which interact nonlinearly terminate avalanches, are characterized. A depletion range >20 keV, leading to sudden drops up 40% neutron rate over 1 ms, observed a broad spatial...
A high temperature field reversed configuration (FRC) has been produced in the newly built, world’s largest compact toroid (CT) facility, C-2, by colliding and merging two high-β CTs using advanced field-reversed θ-pinch technology. This long-lived, stable merged state exhibits following key properties: (1) apparent increase poloidal flux from first pass to final state, (2) significantly improved confinement compared conventional FRCs with decay rates approaching classical values some cases,...
Abstract An economic magnetic fusion reactor favours a high ratio of plasma kinetic pressure to in well-confined, hot with low thermal losses across the confining field. Field-reversed configuration (FRC) plasmas are potentially attractive as concept, achieving simple axisymmetric geometry. Here, we show that FRC have unique, beneficial microstability properties differ from typical regimes toroidal confinement devices. Ion-scale fluctuations found be absent or strongly suppressed core,...
The major objective of the National Spherical Torus Experiment (NSTX) is to understand basic toroidal confinement physics at low aspect ratio and high βT in order advance spherical torus (ST) concept. In do this, NSTX utilizes up 7.5 MW neutral beam injection, 6 harmonic fast waves (HHFWs), it operates with plasma currents 1.5 MA elongations 2.6 a field 0.45 T. New facility, diagnostic modelling capabilities developed over past two years have enabled research team make significant progress...
Large field reversed configurations (FRCs) are produced in the C-2 device by combining dynamic formation and merging processes. The good confinement of these FRCs must be further improved to achieve sustainment with neutral beam (NB) injection pellet fuelling. A plasma gun is installed at one end attempt electric control FRC edge layer. inward radial counters usual spin-up mitigates n = 2 rotational instability without applying quadrupole magnetic fields. Better centering also obtained,...
Nuclear fusion is a potential source of carbon-free electricity with many concepts in development. The Portable and Adaptable Neutron Diagnostics for Advancing Fusion Energy Science (PANDA-FES) suite has been deployed since 2021 to measure neutron yield, energy, spatiotemporal location at two different Z-pinch devices. This diagnostic can be used variety facilities pursuing the magnetic, inertial, magneto-inertial regimes. These regimes have wide range time scales from less than 100 ns few...
Neutral beam injection into a plasma with negative central shear produces rich spectrum of toroidicity-induced and reversed-shear Alfvén eigenmodes in the DIII-D tokamak. The application fast-ion D α (FIDA) spectroscopy shows that profile is flattened inner half discharge. Neutron equilibrium measurements corroborate FIDA data. temporal evolution current also strongly modified. Studies similar discharges show flattening correlates mode amplitude both types modes correlate transport....
The National Spherical Torus Experiment (NSTX) has made considerable progress in advancing the scientific understanding of high performance long-pulse plasmas needed for future spherical torus (ST) devices and ITER.Plasma durations up to 1.6 s (five current redistribution times) have been achieved at plasma currents 0.7 MA with non-inductive fractions above 65% while simultaneously achieving β T N values 17% 5.7 (%m -1 ), respectively.A newly available motional Stark effect diagnostic...
Reversed shear Alfvén eigenmodes (RSAEs) are typically thought of as being localized near the minima in magnetic safety factor profile, however, their spatial coupling to global toroidal (TAEs) has been observed DIII-D discharges. For a decreasing minimum factor, RSAE frequency chirps up through that stable and unstable TAEs. Coupling creates small gap at degeneracy point forming two distinct modes. The core-localized mode structure changes becomes temporarily global. Similarly, crossing...
Experiments with plasmas having nearly equal concentrations of deuterium and tritium have been carried out on TFTR. To date (September 1995), the maximum fusion power has 10.7 MW, using 39.5 MW neutral beam heating, in a supershot discharge 6.7 high beta P following current ramp-down. The density core plasma reached 2.8 MW/m3, exceeding that expected International Thermonuclear Experimental Reactor (ITER). energy confinement time tau E is observed to increase DT, relative D plasmas, by 20%...
The National Spherical Torus Experiment (NSTX) has explored the effects of shaping on plasma performance as determined by many diverse topics including stability global magnetohydrodynamic (MHD) modes (e.g., ideal external kinks and resistive wall modes), edge localized (ELMs), bootstrap current drive, divertor flux expansion, heat transport. Improved capability been crucial to achieving βt∼40%. Precise shape control achieved NSTX using real-time equilibrium reconstruction. simultaneously...
Gas puff Z-pinches are intense sources of X-rays and neutrons but highly susceptible to the magneto-Rayleigh-Taylor instability (MRTI). MRTI mitigation is critical for optimal reproducible yields, motivating significant attention toward various potential mechanisms. One such approach external application an axial magnetic field, which will be discussed here in context recent experiments on Zebra generator (1 MA, 100 ns) at University Nevada, Reno. In these experiments, annular Kr gas liner...
The Tokamak Fusion Test Reactor (TFTR) is a large tokamak which has performed experiments with 50:50 deuterium - tritium fuelled plasmas. Since 1993, TFTR produced about 1090 D T plasmas using 100 grams of and producing 1.6 GJ fusion energy. These have significant populations 3.5 MeV alphas (the charged product). research focused on alpha particle confinement, driven modes, heating studies. Maximum power production aided these studies, requiring simultaneously operation at high input energy...
The Dα light emitted by neutralized deuterium fast ions is measured in magnetohydrodynamics (MHD)-quiescent, magnetically confined plasmas during neutral beam injection. A weighted Monte Carlo simulation code models the fast-ion spectra based on distribution function calculated classically TRANSP [R. V. Budny, Nucl. Fusion 34, 1247 (1994)]. spectral shape excellent agreement and magnitude also has reasonable agreement. signal expected dependencies various parameters including injection...
Purely alpha-particle-driven toroidal Alfvén eigenmodes (TAEs) with mode numbers n=1–6 have been observed in deuterium–tritium (D–T) plasmas on the tokamak fusion test reactor [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)]. The appearance of activity following termination neutral beam injection q(0)>1 is generally consistent theoretical predictions TAE stability [G. Y. Fu et al. Phys. Plasmas 3, 4036 (1996)]. Internal reflectometer measurements compared calculations...