A5043982731- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Magnetic confinement fusion research
- Laser-Matter Interactions and Applications
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- Laser Design and Applications
- Gamma-ray bursts and supernovae
- Ion-surface interactions and analysis
- Cold Fusion and Nuclear Reactions
- Ionosphere and magnetosphere dynamics
- Electromagnetic Launch and Propulsion Technology
- Astro and Planetary Science
- Combustion and Detonation Processes
- Pulsed Power Technology Applications
- Space Technology and Applications
- Astronomy and Astrophysical Research
- Energetic Materials and Combustion
- Advanced X-ray Imaging Techniques
- Geomagnetism and Paleomagnetism Studies
- Mass Spectrometry Techniques and Applications
- Astronomical Observations and Instrumentation
- Plasma Diagnostics and Applications
Energetics (United States)
2014-2024
University of Rochester
2014-2024
Applied Energetics (United States)
2018-2021
Utah State University
2021
Sandia National Laboratories
2015-2018
National Cheng Kung University
2017-2018
General Atomics (United States)
2015
Instituto Superior Técnico
2004-2013
Centre National de la Recherche Scientifique
1999-2011
Centre Lasers Intenses et Applications
2011
Protons with energies up to 18 MeV have been measured from high density laser-plasma interactions at incident laser intensities of 5x10(19) W/cm(2). Up 10(12) protons greater than 2 were observed propagate through a 125 &mgr;m thick aluminum target and measurements their angular deflection made. It is likely that the originate front surface are bent by large magnetic fields which exist in interior. To agree our these would be excess 30 MG generated beam fast electrons also observed.
The formation of strong, high Mach number (2-3), electrostatic shocks by laser pulses incident on overdense plasma slabs is observed in one- and two-dimensional particle-in-cell simulations, for a wide range intensities, pulse durations, target thicknesses, densities. propagate undisturbed across the plasma, accelerating ions (protons). For dimensionless field strength parameter a(0)=16 (Ilambda(2) approximately 3 x 10(20) W cm(-2) microm(2), where I intensity lambda wavelength), thicknesses...
The interaction of short-pulse high-intensity lasers with solid targets generates large numbers energetic electrons. electrons can only penetrate into the if supply an equivalent charge-neutralizing return current. We develop a simple model which shows that in many cases cannot support required current and fast are confined by electric fields to surface target. target response laser irradiation depends strongly on electrical conductivity solid.
Metal foil targets were irradiated with 1 mum wavelength (lambda) laser pulses of 5 ps duration and focused intensities (I) up to 4x10;{19} W cm;{-2}, giving values both Ilambda;{2} pulse comparable those required for fast ignition inertial fusion. The divergence the electrons accelerated into target was determined from spatially resolved measurements x-ray K_{alpha} emission transverse probing plasma formed on back foils. Comparison other published data shows that it increases is...
Fast Ignition Inertial Confinement Fusion is a variant of inertial fusion in which DT fuel first compressed to high density and then ignited by relativistic electron beam generated fast (< 20 ps) ultra-intense laser pulse, usually brought the dense plasma via inclusion re-entrant cone. The transport this from cone apex into critical part scheme, as it can strongly influence overall energetics. Here we review progress theory numerical simulation context Ignition. Important aspects basic...
The transport of fast electrons generated by 1 ps, $\ensuremath{\mu}\mathrm{m}$ wavelength laser pulses focused to spot diameters 20 and peak intensities up $2\ifmmode\times\else\texttimes\fi{}{10}^{18}$ W ${\mathrm{cm}}^{\ensuremath{-}2}$ on solid aluminum targets is considered using a relativistic Fokker-Planck equation, which solved reducing it an equivalent system stochastic differential equations. background represented $\mathbf{E}=\ensuremath{\eta}{\mathbf{j}}_{b},$ where...
Novel features of plasma generation by 1 ps, $1\ensuremath{\mu}\mathrm{m}$, $\ensuremath{\sim}{10}^{19}\mathrm{W}{\mathrm{cm}}^{\ensuremath{-}2}$ laser pulses on thick plastic targets are presented: (i) The electron distribution in the ablated has a minimum along target normal which persists long after pulse $(>1\mathrm{ns})$; (ii) narrow jet is formed at rear surface few picoseconds, line with focus. This consistent beam fast electrons traveling through target, collimated magnetic field target.
Kalpha x-ray emission, extreme ultraviolet and plasma imaging techniques have been used to diagnose energy transport patterns in copper foils ranging thickness from 5 75 microm for intensities up 5x10(20) W cm-2. The emission shadowgrams both indicate a larger divergence angle than that reported the literature at lower [R. Stephens, Phys. Rev. E 69, 066414 (2004)]. Foils thick show triple-humped expansion back front surfaces. Hybrid code modeling shows this can be attributed an increase mean...
The inverse Faraday effect is usually associated with circularly polarized radiation; here, we show that it can also occur for linearly radiation. quasistatic axial magnetic field generated by a laser propagating in plasma be calculated considering both the spin and orbital angular momenta of pulse. A net present when radiation momentum if there any deviation from perfect rotational symmetry. gives an additional contribution to enhance or reduce attributed circular polarization strongly...
An all-optical approach to laser-proton acceleration enhancement is investigated using the simplest of target designs demonstrate application-relevant levels energy conversion efficiency between laser and protons. Controlled deposition energy, in form a double-pulse temporal envelope, combination with thin foil targets which recirculation laser-accelerated electrons can lead optimal conditions for coupling drive into proton beam. This shown deliver substantial 5–30 MeV protons, compared...
The application of an external 26 Tesla axial magnetic field to a D2 gas-filled capsule indirectly driven on the National Ignition Facility is observed increase ion temperature by 40% and neutron yield factor 3.2 in hot spot with areal density approaching what required for fusion ignition [1]. improvements are determined from energy spectral measurements 2.45 MeV neutrons D(d,n)3He reaction, compressed central core B estimated be ∼4.9 kT using 14.1 secondary D(T,n)4He reactions. experiments...
Fast electron generation and propagation were studied in the interaction of a green laser with solids. The experiment, carried out LULI TW (350 fs, 15 J), used K(alpha) emission from buried fluorescent layers to measure transport. Results for conductors (Al) insulators (plastic) are compared simulations: plastic, inhibition fast electrons is observed, due electric fields which become dominant factor
Energetic protons up to 30 MeV have been measured from high intensity laser interactions (⩽5×1019 W/cm2) with solid density plasmas. Up 1012 (&gt; 2 MeV) were observed at the rear of thin aluminum foil targets and measurements their angular deflection made. Similar energies ions produced front foils. Nuclear activation track detector suggest that originate surface target are bent by large magnetic fields exist in plasma interior, which likely generated a laser-produced beam fast electrons.
The interaction of a relativistic electron with dense plasma is studied in the context inertial fusion fast ignition. Expressions for stopping power and deflection are given implemented three-dimensional (3D) Monte Carlo code. Electron range penetration depth computed as functions energy parameters; approximate expressions also proposed. Conditions ignition by including 3D code 2D hydrodynamic required beam determined function mean monoenergetic exponential distributions uniform initial...
The heating of plane solid targets by the Vulcan petawatt laser at powers 0.32–0.73 PW and intensities up to 4×1020 W cm−2 has been diagnosed with a temporal resolution 17 ps spatial 30 μm, measuring optical emission from opposite side target streak camera. Second harmonic was filtered out viewed an angle eliminate transition radiation. Spatial obtained imaging onto bundle fibre optics, arranged into one-dimensional array camera entrance. results show that region 160 μm in diameter can be...
Target studies for the proposed High Power Laser Energy Research (HiPER) facility [M. Dunne, Nature Phys. 2, 2 (2006)] are outlined and discussed. HiPER will deliver a 3ω (wavelength λ=0.35μm), multibeam, multi-ns pulse of about 250kJ 2ω or 70–100kJ in 15ps. Its goal is demonstration laser driven inertial fusion via fast ignition. The baseline target concept direct-drive single shell capsule, ignited by hot electrons generated conically guided ultraintense beam. paper first discusses...
Time-resolved K(α) spectroscopy has been used to infer the hot-electron equilibration dynamics in high-intensity laser interactions with picosecond pulses and thin-foil solid targets. The measured K(α)-emission pulse width increases from ~3 6 ps for intensities ~10(18) 10(19) W/cm(2). Collisional energy-transfer model calculations suggest that hot electrons mean energies ~0.8 2 MeV are contained inside target. inferred broadly consistent ponderomotive scaling over relevant intensity range.
A laser-driven, magnetized liner inertial fusion (MagLIF) experiment is designed for the OMEGA Laser System by scaling down Z point design to provide first experimental data on MagLIF scaling. delivers roughly 1000× less energy than Z, so target linear dimensions are reduced factors of ∼10. Magneto-inertial electrical discharge system could an axial magnetic field 10 T. Two-dimensional hydrocode modeling indicates that a single beam can preheat fuel mean temperature ∼200 eV, limited mix...
Efficient coupling of laser energy into hohlraum targets is important for indirect drive ignition. Laser-plasma instabilities can reduce coupling, symmetry, and cause preheat. We consider the effects an external magnetic field on laser-energy in targets. Experiments were performed at Omega Laser Facility using low-Z gas-filled which placed a coil with Bz ≤ 7.5-T. found that = 7.5-T aligned along axis results up to 50% increase plasma temperature as measured by Thomson scattering. The...
The magnetized resistivity and electrothermal tensors when substituted into the induction equation lead to magnetic field generation, resistive diffusion, advection due gradients, temperature currents. terms driven by gradient current have cross components (perpendicular both driving term) that depend on significantly modified versions of Braginskii's transport coefficients [S. I. Braginskii, in Reviews Plasma Physics, edited M. A. Leontovich (Consultants Bureau, New York, 1965), Vol. 1, p....
Energetic charged particles generated by inertial confinement fusion (ICF) implosions encode information about the spatial morphology of hotspot and dense fuel during time peak reactions. The knock-on deuteron imager (KoDI) was developed at Omega Laser Facility to image these in order diagnose low-mode asymmetries layer cryogenic deuterium–tritium ICF implosions. However, images collected are distorted several ways that prevent reconstruction source. In this paper, we describe distortions a...
The transport of fast electrons generated by a 1 ps, 20 J, ${10}^{19} {\mathrm{W}\mathrm{}\mathrm{cm}}^{\ensuremath{-}2},$ $1 \ensuremath{\mu}\mathrm{m}$ wavelength laser pulse through $70--250 thick deuterated polyethylene (CD2) targets is modeled with Fokker-Planck hybrid code in $r\ensuremath{-}z$ geometry. Initially, electric field generation inhibits propagation, which then proceeds the formation low resistivity channel due to Ohmic heating. magnetic at edge leads strong collimation....
Filamentary ionization tracks have been observed via optical probing inside Al-coated glass targets after the interaction of a picosecond 20-TW laser pulse at intensities above ${10}^{19}\phantom{\rule{0ex}{0ex}}\mathrm{W}/{\mathrm{cm}}^{2}$. The tracks, up to $700\ensuremath{\mu}\mathrm{m}$ in length and between 10 $20\ensuremath{\mu}\mathrm{m}$ width, originate from focal spot region beam. Simulations performed with 3D particle-in-cell 2D Fokker-Planck hybrid codes indicate that...
The interaction of a high-intensity laser with solid target generates large current fast electrons flowing into the target. Due to value current, generate significant electric and magnetic fields in rapidly heat it high temperatures. However, these effects were neglected interpreting x-ray emission experiments, so details electron generation that inferred could be incorrect. This is considered, theoretically, for layered target, Kalpha by using hybrid Monte Carlo code includes field...