G. A. Wurden
A5054245371- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Fusion materials and technologies
- Plasma Diagnostics and Applications
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- Solar and Space Plasma Dynamics
- Dust and Plasma Wave Phenomena
- Atomic and Molecular Physics
- Nuclear reactor physics and engineering
- High-pressure geophysics and materials
- Astro and Planetary Science
- Atomic and Subatomic Physics Research
- Electromagnetic Launch and Propulsion Technology
- Spacecraft and Cryogenic Technologies
- Cold Fusion and Nuclear Reactions
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Calibration and Measurement Techniques
- Geomagnetism and Paleomagnetism Studies
- Astronomy and Astrophysical Research
- Optical Systems and Laser Technology
Los Alamos National Laboratory
2015-2024
University of Maryland, College Park
2024
Max Planck Society
1989-2019
Max Planck Institute for Plasma Physics
1989-2019
Los Alamos National Security (United States)
2007-2018
HUN-REN Wigner Research Centre for Physics
2016-2018
Sandia National Laboratories
2017
Gwangju Institute of Science and Technology
2017
Spectral Sciences (United States)
2017
Technical University of Darmstadt
2017
Neutrons are unique particles to probe samples in many fields of research ranging from biology material sciences engineering and security applications. Access bright, pulsed sources is currently limited large accelerator facilities there has been a growing need for compact over the recent years. Short pulse laser driven neutron could be relatively cheap way produce neutrons with energies excess 10 MeV. For more than decade experiments have tried obtain numbers sufficient Our demonstrated an...
After completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning device, first plasma operation started at end 2015. Integral start-up using electron cyclotron resonance heating (ECRH) an extensive set diagnostics have been completed, allowing initial physics studies during operational campaign. Both in helium hydrogen, breakdown was easily achieved. Gaining experience with vessel conditioning, discharge lengths could be extended gradually. Eventually,...
Wendelstein 7-X is the first comprehensively optimized stellarator aiming at good confinement with plasma parameters relevant to a future power plant. Plasma operation started in 2015 using limiter configuration. After installing an uncooled magnetic island divertor, extending energy limit from 4 80 MJ, continued 2017. For this phase, electron cyclotron resonance heating (ECRH) capability was extended 7 MW, and hydrogen pellet injection implemented. The enhancements resulted highest triple...
A significant improvement of plasma parameters in the optimized stellarator W7-X is found after injections frozen hydrogen pellets. The ion temperature post-pellet phase exceeds 3 keV with 5 MW electron heating and global energy confinement time surpasses empirical ISS04-scaling. realized such experiments are significantly above those comparable gas-fuelled discharges. In this paper, we present details these pellet discuss main properties during enhanced phases. Local power balance applied...
Research in NSTX has been conducted to establish spherical torus plasmas be used for high β, auxiliary heated experiments. This device a major radius R0 = 0.86 m and midplane halfwidth of 0.7 m. It operated with toroidal magnetic field B0 ⩽ 0.3 T Ip 1.0 MA. The evolution the plasma equilibrium is analysed between discharges an automated version EFIT code. Limiter, double null lower single diverted configurations have sustained several energy confinement times. stored reached 92 kJ (βt 17.8%)...
In this community white paper, we describe an approach to achieving fusion which employs a hybrid of elements from the traditional magnetic and inertial concepts, called magneto-inertial (MIF). The status MIF research in North America at multiple institutions is summarized including recent progress, opportunities, future plans.
Wendelstein 7-X aims at quasi-steady state operation with up to 10 MW of heating power for 30 min. Power exhaust will be handled predominantly via actively water cooled CFC (carbon-fiber-reinforced carbon) based divertor units designed withstand loads MW/m2 locally in steady state. If local exceed this value, a risk delamination the and failure entire modules arises. Infrared endoscopes monitor all main plasma facing components are being prepared, near real time software tools under...
Laser-plasma interactions in the novel regime of relativistically induced transparency (RIT) have been harnessed to generate intense ion beams efficiently with average energies exceeding 10 MeV/nucleon (>100 MeV for protons) at "table-top" scales experiments LANL Trident Laser. By further optimization laser and target, RIT has extended into a self-organized plasma mode. This mode yields an beam much narrower energy spread while maintaining high conversion efficiency. involves self-generation...
Laser-driven neutrons are generated by the conversion of laser-accelerated ions via nuclear reactions inside a converter material. We present results from an experimental campaign at PHELIX laser GSI in Darmstadt where protons and deuterons were accelerated thin deuterated plastic foils with thicknesses μm sub-μm range. The sandwich-type beryllium converter, leading to reproducible neutron numbers around 1011 per shot. angular distribution was measured high level detail using up 30 bubble...
Abstract Wendelstein 7-X (W7-X), the largest advanced stellarator, is built to demonstrate high power, performance quasi-continuous operation. Therefore, in recent campaign, experiments were performed prepare for long pulse operation, addressing three critical issues: development of stable detachment, control heat and particle exhaust, impact leading edges on plasma performance. The exhaust W7-X realized with help an island divertor, which utilizes large magnetic islands at boundary. This...
Turbulent filaments in visible light emission corresponding mainly to density fluctuations at the edge have been observed large aspect ratio tokamaks: TFTR, ASDEX, Alcator C-Mod, and DIII-D. This article reports on similar turbulent structures National Spherical Torus Experiment (NSTX) using a fast-framing, intensified, digital camera. These were previously detected high recycling regions, such as limiters or antennas, where line from neutral atoms was modulated by local plasma density....
The gas puff imaging (GPI) diagnostic can be used to study the turbulence present at edge of magnetically confined plasmas. In this instantaneous two-dimensional (2D) radial vs poloidal structure is measured using fast-gated cameras and discrete fast chords. By a controlled neutral puff, typically helium or deuterium, brightness contrast turbulent emission fluctuations are increased independently natural recycling. addition, recent advances in ultrafast framing allow followed time. itself...
A new method of actively modifying the plasma-wall interaction was tested on Tokamak Fusion Test Reactor. laser used to introduce a directed lithium aerosol into discharge scrape-off layer. The introduced in this fashion ablated and migrated preferentially limiter contact points. This allowed be influenced situ real time by external means. Significant improvement energy confinement fusion neutron production rate as well reduction plasma Zeff have been documented neutral beam heated plasma....
The edge plasma of the ZT-40M [Fusion Technol. 8, 1571 (1985)] reversed-field pinch has been studied using a combination three different probes: double-swept Langmuir probe, an electrostatic energy analyzer, and calorimeter–Langmuir probe. measured both with without movable graphite tile limiter present nearby in plasma. Without fast nonthermal tail electrons (T≂350 eV) is detected nearly unidirectional flow along B having density between 2% 10% cold (T≂20 eV). toroidal sense this electron...
Parametric dependences of the heat flux footprint on outer divertor target plate are explored in EDA H-mode and ohmic L-mode plasmas over a wide range parameters with attached plasma conditions.Heat profile shapes found to be independent toroidal field strength, power flow along magnetic lines insensitive x-point topology (single-null versus double-null).The magnitudes widths closely follow that "upstream" pressure profile, which correlated thermal energy content current.Heat decay lengths...
The Wendelstein 7-X (W7-X) optimized stellarator fusion experiment, which went into operation in 2015, has been operating since 2017 with an un-cooled modular graphite divertor. This allowed first divertor physics studies to be performed at pulse energies up 80 MJ, as opposed 4 MJ the phase, where five inboard limiters were installed instead of a This, and number other upgrades device capabilities, extension regimes higher plasma density, heating power, performance overall, e.g. setting new...
Abstract Classical particle drifts are known to have substantial impacts on fluxes of particles and heat through the edge plasmas in both tokamaks stellarators. Here we present results from first dedicated investigation drift effects W7-X stellarator. By comparing similar plasma discharges conducted with a forward- reverse-directed magnetic field, could be isolated observation up-down asymmetries flux profiles divertor targets. In low-density plasmas, radial locations strike lines (i.e....
High-pressure noble gas jet injection is a mitigation technique which potentially satisfies the requirements of fast response time and reliability, without degrading subsequent discharges. Previously reported experiments on DIII-D showed good success at reducing deleterious disruption effects. In this paper, results recent Alcator C-Mod are reported. Jointly, these have greatly improved understanding dynamics processes involved in mitigating both machines, sequence events following observed...
Ion Bernstein wave excitation and propagation via finite ion-Larmor-radius mode transformation are investigated theoretically experimentally. It is shown that in the ion cyclotron range of frequencies ω≲4Ωi, with modest temperatures (Ti≲10 eV), finite-Larmor-radius effect removes singularity at lower-hybrid resonance layer, enabling an externally initiated electron plasma to transform continuously into wave. In ACT-1 hydrogen (Te≂2.5 eV, Ti≲2.0 excited waves have been observed for ω≲2Ωi as...
We present a full characterization of short pulse laser-driven neutron source. Neutrons are produced by nuclear reactions ions deposited in secondary target. The emission neutrons is superposition an isotropic component into 4π and forward directed, jet-like contribution, with energies ranging up to 80 MeV. A maximum flux 4.4 × 109 neutrons/sr has been observed used for fast radiography. On-shot the ion driver beam done variety different diagnostics, including particle detectors, reaction,...
Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters December 2015. At end of 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were operation, allowing detailed studies many interesting plasma phenomena. For example, fast neutral gas manometers supported video cameras (including one fast-frame camera frame rates...
Emerging approaches to short-pulse laser-driven neutron production offer a possible gateway compact, low cost, and intense broad spectrum sources for wide variety of applications. They are based on energetic ions, driven by an laser, interacting with converter material produce neutrons via breakup nuclear reactions. Recent experiments performed the high-contrast laser at Trident facility Los Alamos National Laboratory have demonstrated ion acceleration mechanism operating in regime...