A5028328733- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Pulsed Power Technology Applications
- Vacuum and Plasma Arcs
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Electromagnetic Launch and Propulsion Technology
- Gamma-ray bursts and supernovae
- Laser-Matter Interactions and Applications
- Electrostatic Discharge in Electronics
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Lightning and Electromagnetic Phenomena
- Particle accelerators and beam dynamics
- Plasma Applications and Diagnostics
- Modular Robots and Swarm Intelligence
- Gyrotron and Vacuum Electronics Research
- Dust and Plasma Wave Phenomena
- nanoparticles nucleation surface interactions
- Advanced X-ray Imaging Techniques
- Fusion materials and technologies
- Diamond and Carbon-based Materials Research
- High-pressure geophysics and materials
University of California, San Diego
2014-2024
Imperial College London
2009-2024
First Light Fusion
2024
Lawrence Livermore National Laboratory
2023
Energetics (United States)
2023
University of Washington
2023
Manufacturing Advocacy & Growth Network (United States)
2023
Sandia National Laboratories
2009
Observatoire de Paris
2009
Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères
2009
The objectives of this tutorial are as follows: 1) to help students and researchers develop a basic understanding how pulsed-power systems used create high-energy-density (HED) matter; 2) new, compact, efficient technology called linear transformer drivers (LTDs); 3) understand why LTDs an attractive for driving HED physics (HEDP) experiments; 4) contrast with the more traditional Marx-generator/pulse-forming-line approach HEDP 5) briefly review history LTD well some LTD-driven research...
The sheared-flow-stabilized Z pinch concept has been studied extensively and is able to produce fusion-relevant plasma parameters along with neutron production over several microseconds. We present here elevated electron temperature results spatially temporally coincident the source. An optical Thomson scattering apparatus designed for FuZE device measures temperatures in range of 1–3 keV on axis device, 20 cm downstream nose cone. 17-fiber system radial profiles temperature. Scanning laser...
We report the first optical Thomson scattering measurements inside a high electron temperature (≳1 keV) and moderate density (mid 1016 cm−3) plasma. This diagnostic has been built to provide critical plasma parameters, such as density, for Advanced Research Projects Agency-Energy-supported fusion-energy concepts. It uses an 8 J laser at 532 nm in 1.5 ns measure frequency feature of profile 17 locations along probe axis. is able from 5 × 1017 cm−3 several 1019 temperatures tens eV keV. Here,...
We present an experimental study of the development and structure bow shocks produced by interaction a magnetised, collisional, super-Alfvénic plasma flow with conducting cylindrical obstacles. The embedded, frozen-in magnetic field (ReM ∼ 20) is current-driven ablation fine aluminium wires in inverse, exploding wire array z-pinch. show that orientation embedded respect to obstacles has dramatic effect on shock structure. When aligned obstacle, sharp formed global determined simply fast...
We present a study of the formation bow shocks in radiatively cooled plasma flows. This work uses an inverse wire array to provide quasi-uniform, large scale hydrodynamic flow accelerated by Lorentz forces supersonic velocities. impacts stationary object placed its path, forming well-defined Mach cone. Interferogram data are used determine number ∼6, which may increase with radial position suggesting strongly cooling flow. Self-emission imaging shows thin (<60 μm) emitting shock region,...
The dynamics and characteristics of the plasma sheath during axial phase in a ∼300 kA, ∼2 kJ dense focus using static gas load Ne at 1–4 Torr are reported. sheath, which is driven axially constant velocity ∼105 m/s by j × B force, observed optical imaging, to form an acute angle between electrodes. This becomes more (more parallel axis) along rundown. average thickness nearer anode 0.69 ± 0.02 mm cathode 0.95 mm. total mass increases from 1 μg 6 over pressure range Torr. However, fraction...
Recent pulsed-power experiments have demonstrated the formation of astrophysically relevant, differentially rotating plasmas. Key features plasma flows are discovery a quasi-Keplerian rotation curve, launching highly collimated angular-momentum-transporting axial jets, and hollow density structure sustained by centrifugal barrier effect. In this communication, we discuss several in these through order-of-magnitude models. First, show that observed velocity would produce force strong enough...
Modeling of the trajectories VLBI components ejected by nucleus 1928+738 shows jet contains three families trajectories, i.e. are from different origins. The fit C1, C6 and C8 indicates that two binary black hole systems. first system is associated with stationary Cg CS characterized a radius $R_{bin,1} \approx 0.220$ mas; both holes quasi regularly between 1990 2010. second not $R_{bin,2} 0.140$ it only 1994 1999. sytems separated $\approx 1.35$ mas. We briefly discuss consequences...
We describe a technique by which magnetic field probes are used to triangulate the exact position of breakdown in high voltage coaxial vacuum gap. An array three is placed near plane gap with each probe at 90° intervals around outer (anode) electrode. These measure azimuthal component and all same radial distance from cylindrical axis. Using peak values measured probe, current carried channel, Ampères law we can calculate away that occurred. calculated distances then draw circles centered...
We present an experimental study of plasma initiation a solid metal liner at the 1 MA level. In contrast to previous work, we introduce vacuum gap one connections power feed investigate how this affects and infer may affect symmetry in compression experiments. observed that causes non-uniform both azimuthally axially liners, diagnosed by gated optical imaging. Using magnetic field probes external liner, also determined emission is strongly linked current distribution liner. The apparent...
We present a study of the time varying current density distribution in solid metallic liner experiments at 1 MA level. Measurements are taken using an array magnetic field probes which provide 2D triangulation average centroid drive load 3 discrete axial positions. These data correlated with gated optical self-emission imaging directly images breakdown and plasma formation region. Results show that is azimuthally non-uniform changes significantly throughout 100 ns experimental timescale....
We report the plasma pressure reached inside central column of a sheared-flow-stabilized Z-pinch using Thomson scattering measurements. Building on previously reported experimental results and analysis methods established for high temperature moderate density plasmas generated FuZE device, we show evidence region with higher electron density, which is consistent pinch behavior. Elevated temperatures up to 2.25 ± 0.8 keV densities (4.9±0.2)×1017 cm−3 are observed temporally coincide fusion...
Recent work reported on the current density in pulsed-power-driven liners where a vacuum gap was introduced power feed connecting liner to generator. The resultant flashover generates azimuthally localized current-carrying plasma channels, which can create an azimuthal nonuniformity density. evolves during pulse, but is observed through experiment timescale. Magnetohydrodynamic simulation 3-D demonstrates difficulty reproducing experimental data within limited computational domain, and those...
Radial wire array Z-pinches, where wires are positioned radially outward from a central cathode to concentric anode, can act as compact bright X-ray source that could potentially be used drive hohlraum. Experiments were performed on the 7-MA Saturn generator using radial arrays. These experiments studied number of potential risks in scaling arrays up 1-MA level, they have been shown promising source. Data indicate at 7 MA, radiate ~9 TW with 10-ns full-width half-maximum pinch.
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A free space collective Thomson scattering system has been developed to study pulsed power produced plasmas. While most diagnostics on machines use a bundle of fibers couple scattered light from the plasma spectrometer, this used coupling light, which enabled spatially continuous image plasma. Initial experiments with diagnostic were performed an inverse wire array generated by 200 kA, 1100 ns rise time pulse generator. The capabilities demonstrated using low frequency ion acoustic wave...
Highly collimated outflows or jets are produced by a number of astrophysical objects including protostars. The morphology and collimation these is thought to be strongly influenced the effects radiative cooling, angular momentum interstellar medium surrounding jet. Astrophysically relevant experiments performed with conical wire array z‐pinches investigating each effects. It possible in case enter appropriate parameter regime, leading way towards future where different techniques can more...
We present an experimental analysis of the symmetry current density in a coaxial geometry, diagnosed using magnetic field probe array and calculations Fowler-Nordheim enhancement factor. Data were collected on gap breakdown device (240 A, 25 kV, 150 ns, ∼0.1 Hz), data from experiments 2 different sizes penetration depths are compared over runs comprising 50 shots for each case. The quantifies distribution at three axial locations, either sides vacuum breakdown, tracks evolution with time...
We present measurements from laser-produced plasmas generated using cryogenic Xe targets and quantify the emission characteristics in soft x-ray region (1 to 6 nm). The system is based on a LN2-cooled rotating drum, which allows for high repetition rate, Nd:YAG laser systems with energies up 325 mJ on-target pulse lengths of 130 ps, 600 or 6.5 ns. High resolution spectra are measured grazing incidence spectrometer, we first quantitative conversion efficiency (CE) this range. Data show CE...
Summary form only given. Results on coordinated experiments and MHD simulations magnetically driven dense plasma focus implosions are presented. The aim of this effort is to use a repetitively fired (DPF) gather data from 100's 1000's shots, so as better refine numerical codes. emphasis research current diffusion heat transport in implosions. experimental results will feed the first fully 3D DPF devices, adding new capabilities GORGON code.Experiments run at DPF-3, Mather-type PF based...
Summary form only given. We present a study of the formation bow shocks in radiatively-cooled plasma flows, where magnetic field can be introduced. This work uses XP generator (260kA, 145ns) at Cornell University to drive an inverse wire array. A quasi-uniform, large scale hydrodynamic flow is generated and accelerated by Lorentz forces high Mach numbers. impacts stationary object placed its path, forming well-defined cone. In case, shock front very narrow (~60μm) shows strong cooling...