A5046011756- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Atomic and Molecular Physics
- Plasma Diagnostics and Applications
- High-pressure geophysics and materials
- Fluid Dynamics and Turbulent Flows
- Laser Design and Applications
- Laser-Matter Interactions and Applications
- Dust and Plasma Wave Phenomena
- Gas Dynamics and Kinetic Theory
- Astrophysics and Cosmic Phenomena
- Plasma and Flow Control in Aerodynamics
- Electromagnetic Launch and Propulsion Technology
- Pulsed Power Technology Applications
- Energetic Materials and Combustion
- Fusion materials and technologies
- Semiconductor Quantum Structures and Devices
- Advanced Optical Sensing Technologies
- Nuclear Physics and Applications
- Computational Fluid Dynamics and Aerodynamics
Lawrence Livermore National Laboratory
2016-2025
Energetics (United States)
2016-2023
University of Washington
2023
University of California, San Diego
2009-2023
Centre Lasers Intenses et Applications
2020
Centre National de la Recherche Scientifique
2020
University of York
2020
Université de Bordeaux
2020
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2020
Osaka University
2017-2019
This paper, extended from a Letter [Chen et al., Phys. Rev. E 110, L013201 (2024)] published in 2024, presents detailed results set of experiments studying the x-ray drive produced laser-heated ignition-scale hohlraums at National Ignition Facility. The reveal that deficiencies non-local thermodynamic equilibrium atomics physics calculations gold emissivity lead to overestimation “M-band” radiation and are responsible for discrepancies predictions vs measurements these hohlraums. These were...
A series of experiments has been conducted in order to investigate the azimuthal structures formed by interactions cylindrically converging plasma flows during ablation phase aluminium wire array Z pinch implosions. These were carried out using 1.4 MA, 240 ns MAGPIE generator at Imperial College London. The main diagnostic used this study was a two-colour, end-on, Mach-Zehnder imaging interferometer, sensitive axially integrated electron density plasma. data collected these reveal strongly...
A suite of laser based diagnostics is used to study interactions magnetised, supersonic, radiatively cooled plasma flows produced using the Magpie pulse power generator (1.4 MA, 240 ns rise time). Collective optical Thomson scattering measures time-resolved local flow velocity and temperature across 7–14 spatial positions. The spectrum recorded from multiple directions, allowing more accurate reconstruction vectors. areal electron density measured 2D interferometry; optimisation analysis are...
We report on the detection of time-dependent B-field amplitude and topology in a laser-driven solenoid. The inferred from both proton deflectometry Faraday rotation ramps up linearly time reaching 210 ± 35 T at end 0.75-ns laser drive with 1 TW 351 nm. A lumped-element circuit model agrees well linear rise suggests that blow-off plasma screens field between plates leading to an increased plate capacitance converts laser-generated hot-electron current into voltage source drives through ALE3D...
A study of the transition from collisional to collisionless plasma flows has been carried out at National Ignition Facility using high Mach number (M>4) counterstreaming plasmas. In these experiments, CD-CD and CD-CH planar foils separated by 6–10 mm are irradiated with laser energies 250 kJ per foil, generating ∼1000 km/s flows. Varying foil separation distance scales ion density average bulk velocity and, therefore, ion-ion Coulomb mean free path, interaction region midplane. The...
We present a detailed study of magnetic reconnection in quasi-two-dimensional pulsed-power driven laboratory experiment. Oppositely directed fields ($B=3\text{ }\text{ }\mathrm{T}$), advected by supersonic, sub-Alfv\'enic carbon plasma flows (${V}_{\mathrm{in}}=50\text{ }\mathrm{km}/\mathrm{s}$), are brought together and mutually annihilate inside thin current layer ($\ensuremath{\delta}=0.6\text{ }\mathrm{mm}$). Temporally spatially resolved optical diagnostics, including interferometry,...
In conventional gases and plasmas, it is known that heat fluxes are proportional to temperature gradients, with collisions between particles mediating energy flow from hotter colder regions the coefficient of thermal conduction given by Spitzer's theory. However, this theory breaks down in magnetized, turbulent, weakly collisional although modifications difficult predict first principles due complex, multiscale nature problem. Understanding transport important astrophysical plasmas such as...
The predicted implosion performance of deuterium-tritium fuel capsules in indirect-drive inertial confinement fusion experiments relies on precise calculations the x-ray drive laser-heated cavities (hohlraums). This requires accurate, spectrally dependent simulations laser to conversion efficiencies and absorption losses hohlraum wall. A set National Ignition Facility have identified a cause for long-standing "drive deficit" as overprediction gold emission at ∼2.5 keV nonlocal thermodynamic...
We present experimental results of the formation magnetically driven plasma jets, showing for first time a way producing episodic jet/ouflows in laboratory. The jets are produced using 6.5 μm thick aluminum disk (a radial foil), which is subjected to 1 MA, 250 ns current pulse from MAGPIE generator [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (1996)]. early motion foil characterized by bulk mass due magnetic pressure, together with surface following direction J×B force. A low density...
A new wire array configuration has been used to create thin shell-like implosions in a cylindrical array. The setup introduces $\ensuremath{\sim}5\text{ }\text{ }\mathrm{kA}$, $\ensuremath{\sim}25\text{ }\mathrm{ns}$ current prepulse followed by $\ensuremath{\sim}140\text{ current-free interval before the application of main ($\ensuremath{\sim}1\text{ }\mathrm{MA}$) pulse. volumetrically heats wires which expand $\ensuremath{\sim}1\text{ }\mathrm{mm}$ diameter leaving no dense core and...
A Thomson scattering diagnostic has been used to measure the parameters of cylindrical wire array Z pinch plasmas during ablation phase. The operates in collective regime (α>1) allowing spatially localized measurements ion or electron plasma temperatures and bulk velocity. flow is found accelerate towards axis reaching peak velocities 1.2-1.3×10(7) cm/s aluminium ∼1×10(7) tungsten arrays. Precursor temperature made shortly after formation are correspond kinetic energy converging flow.
The role of radiative cooling during the evolution a bow shock was studied in laboratory-astrophysics experiments that are scalable to shocks present jets from young stellar objects. laboratory is formed collision two counter-streaming, supersonic plasma produced by an opposing pair radial foil Z-pinches driven current pulse MAGPIE pulsed-power generator. have different flow velocities frame and over many times characteristic time-scale. initially smooth rapidly develops small-scale...
A new experimental platform was developed, based on the use of supersonic plasma flow from ablation stage an inverse wire array z-pinch, for studies shocks in magnetized high energy density physics plasmas a well-defined and diagnosable 1-D interaction geometry. The mechanism generation ensures that (ReM ∼ 50, MS 5, MA 8, Vflow ≈ 100 km/s) has frozen-in magnetic field at level sufficient to affect formed by its with obstacles. It is found addition expected accumulation stagnated thin layer...
We present the first local, quantitative measurements of ion current filamentation and magnetic field amplification in interpenetrating plasmas, characterizing dynamics Weibel instability. The interaction a pair laser-generated, counterpropagating, collisionless, supersonic plasma flows is probed using optical Thomson scattering (TS). Analysis TS ion-feature revealed anticorrelated modulations density two streams at spatial scale skin depth c/ω_{pi}=120 μm, correlated modulation current....
This study investigated discrepancies between measured and simulated x-ray drive in Inertial Confinement Fusion (ICF) hohlraums at the National Ignition Facility (NIF). Despite advances radiation-hydrodynamic simulations, a consistent "drive deficit" remains. Experimentally ICF capsule bang-times are systematically 400-700 ps later than simulations predict. The Build-A-Hohlraum (BAH) campaign explored potential causes for this discrepancy by varying hohlraum features, including laser...
High-energy speckled lasers are known to exert ponderomotive forces on a plasma. This can reduce flow transverse the propagation of beams. When coupled with supersonic flow, this has been shown lead formation shock that travels against flow. Experiments conducted OMEGA laser facility have used Thomson scattering observe density and velocity changes consistent ponderomotively driven shock. Comparisons data hydrodynamic simulations force, particle-in-cell full Maxwell field solver, without...
This study investigated discrepancies between measured and simulated x-ray drive in Indirect-Drive Inertial Confinement Fusion (ID-ICF) hohlraums at the National Ignition Facility. Despite advances radiation-hydrodynamic simulations, a consistent “drive deficit” remains. Experimentally ID-ICF capsule bang-times are systematically 400–700 ps later than simulations predict. The Build-A-Hohlraum (BAH) campaign explored potential causes for this discrepancy by varying hohlraum features,...
An experimental investigation into the interaction of a supersonic, radiatively cooled plasma jet with argon gas is presented. The formed by ablation an aluminum foil driven 1.4 MA, 250 ns current pulse in radial Z-pinch configuration. outflow consists supersonic (Mach number ∼3–5), dense (ion density ni ∼ 1018 cm−3), highly collimated (half-opening angle ∼2°−5°) surrounded lower halo moving same axial velocity as jet. addition above leads to formation shock plasma, together bow-shock...
Many astrophysical systems are effectively “collisionless,” that is, the mean free path for collisions between particles is much longer than size of system. The absence particle does not preclude shock formation, however, as shocks can be result plasma instabilities generate and amplify electromagnetic fields. magnetic fields required formation may either initially present, example, in supernova remnants or young galaxies, they self-generated such gamma-ray bursts (GRBs). In case GRB...
The cumulative impact of multiple laser speckles on a supersonic plasma flow across optically smoothed beams is investigated. bending caused by ponderomotive laser–plasma coupling, together with flow, leads to momentum-conserving response that results in deceleration the flow. Once velocity decreases subsonic level, action can generate shock within plasma. This scenario has been predicted theoretically and confirmed hydrodynamic simulations. conditions generation are given terms pressure,...
We present new experiments to study the formation of radiative shocks and interaction between two counterpropagating shocks. The are performed at Orion laser facility, which is used drive in xenon inside large aspect ratio gas cells. collision their respective precursors, combined with inherently three-dimensional shocks, provides a novel platform particularly suited for benchmarking numerical codes. dynamics before after investigated using point-projection x-ray backlighting while,...
Recent experiments involving directly driven beryllium spheres are reported. Plasma conditions measured using Thomson scattering with the probe beam pointed 200, 300, and 400 μm from surface of sphere. Laser coupling is assessed calorimeters that collect scattered light placed at various locations within target chamber. intensities 1014 W/cm2 2.5×1014 chosen to minimize unmodeled laser-plasma interactions (LPIs) lead laser-target decoupling. Two-dimensional simulations compared interpreted...
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,...