A5089834264- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Laser Design and Applications
- Magnetic confinement fusion research
- Ion-surface interactions and analysis
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Particle accelerators and beam dynamics
- Particle physics theoretical and experimental studies
- Fusion materials and technologies
- Energetic Materials and Combustion
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Combustion and Detonation Processes
- Mass Spectrometry Techniques and Applications
- Pulsed Power Technology Applications
- Cold Fusion and Nuclear Reactions
- Laser Material Processing Techniques
- Advanced Optical Sensing Technologies
- Advanced X-ray Imaging Techniques
- Rocket and propulsion systems research
- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray and CT Imaging
Lawrence Livermore National Laboratory
2012-2024
General Atomics (United States)
2006
Rutherford Appleton Laboratory
2006
Atomic Weapons Establishment
2006
Applied Energetics (United States)
2006
University of California, Davis
2006
Instituto de Psicologia Comportamental de São Carlos
2000
Carnegie Mellon University
1979-1982
Argonne National Laboratory
1980-1981
Weizmann Institute of Science
1978
Ultrahigh intensity lasers can potentially be used in conjunction with conventional fusion to ignite inertial confinement (ICF) capsules a total energy of few tens kilojoules laser light, and possibly lead high gain as little 100 kJ. A scheme is proposed three phases. First, capsule imploded the approach assemble high-density fuel configuration. Second, hole bored through corona composed ablated material, critical density pushed close core by ponderomotive force associated high-intensity...
We use simulations to investigate the interaction of ultra-intense laser pulses with a plasma. With an intensity greater than ${10}^{18}$ W/${\mathrm{cm}}^{2}$, these have pressure ${10}^{3}$ M bar and drive plasma relativistically. Hole boring by light beam is key feature interaction. find substantial absorption into heated electrons characteristic temperature order pondermotive potential. Other effects include dependence on polarization incident light, strong magnetic field generation,...
We consider the production of electron-positron pairs by interaction relativistic superthermal electrons, generated ultraintense laser pulses, with high- $Z$ material. discuss and target parameters required in order to optimize pair-production rate. explore regime when pairs, if sufficiently confined, can start exponentiate number feasibility achieving a pair density approaching ${10}^{21}\mathrm{cm}{}^{\ensuremath{-}3}$, $\frac{1}{50}\mathrm{th}$ that solid-ion density.
In an experimental study of the physics fast ignition, characteristics hot electron source at laser intensities up to 1020 W cm−2 have been measured and a diagnosis heating depth by electrons has initiated. Generation with more than 30% efficiency observed. Preliminary data suggest temperatures kT in range 300–800 eV.
Several targets are described that in simulations give yields of 1–30 MJ when indirectly driven by 0.9–2 0.35 μm laser light. The article describes the targets, modeling was used to design them, and done set specifications for system proposed National Ignition Facility. Capsules with beryllium or polystyrene ablators enclosed gold hohlraums. All designs utilize a cryogenic fuel layer; it is very difficult achieve ignition at this scale noncryogenic capsule. It necessary use multiple bands...
The characteristics of 22–40keV Kα x-ray sources are measured. These high-energy produced by 100TW and petawatt high-intensity lasers will be used to develop implement workable radiography solutions probe high-Z dense materials for the density experiments. measurements show that source size from a simple foil target is larger than 60μm, too large most applications. total yield independent thicknesses, verifying refluxing plays major role in photon generation. Smaller radiating volumes emit...
We report the first direct measurements of total absorption short laser pulses on solid targets in ultrarelativistic regime. The data show an enhanced at intensities above 10(20) W/cm(2), reaching 60% for near-normal incidence and 80%-90% 45 degrees incidence. Two-dimensional particle-in-cell simulations demonstrate that such high is consistent with both interaction preplasma hole boring by intense pulse. A large redshift second harmonic indicates a surface recession velocity 0.035c.
Detailed angle and energy resolved measurements of positrons ejected from the back a gold target that was irradiated with an intense picosecond duration laser pulse reveal are in collimated relativistic jet. The laser-positron conversion efficiency is ∼2×10{-4}. jets have ∼20 degree angular divergence distributions quasimonoenergetic 4 to 20 MeV beam temperature ∼1 MeV. sheath electric field on surface shown determine positron energy. distribution controlled by varying field, through...
Marshall Rosenbluth’s extensive contributions included seminal analysis of the physics laser-plasma interaction and review advocacy inertial fusion program. Over last decade he avidly followed efforts many scientists around world who have studied Fast Ignition, an alternate form fusion. In this scheme, fuel is first compressed by a conventional confinement driver then ignited short (∼10ps) pulse, high-power laser. Due to technological advances, such short-pulse lasers can focus power...
Transport modeling of idealized, cone-guided fast ignition targets indicates the severe challenge posed by fast-electron source divergence. The hybrid particle-in-cell [PIC] code Zuma is run in tandem with radiation-hydrodynamics Hydra to model propagation, fuel heating, and thermonuclear burn. electron based on a 3D explicit-PIC laser-plasma simulation PSC code. This shows quasi two-temperature energy spectrum, divergent angle spectrum (average velocity-space polar 52 degrees). simulations...
Calculations are presented for a high yield inertial fusion design, employing indirect drive with double-ended z-pinch-driven hohlraum radiation source. A current (∼60 MA) accelerator implodes z pinches within an enclosing hohlraum. Radial spoke arrays and shine shields isolate the capsule from pinch plasma, magnetic field, direct x-ray shine. Our approach places minimal requirements on z-pinch uniformity stability, usually problematic due to magneto-Rayleigh–Taylor instability. Large...
The minimum energy needed to ignite an inertial confinement fusion capsule is of considerable interest in the optimization driver. Recent computational work investigating this has found that it depends on implosion history, particular, drive pressure. This dependence examined using a series LASNEX simulations find ignited capsules which have different values velocity, fuel adiabat and It main effect varying pressure alter stagnation capsule, changing its adiabat, which, turn, affects...
The viability of fast-ignition (FI) inertial confinement fusion hinges on the efficient transfer laser energy to compressed fuel via multi-MeV electrons. Preformed plasma due prepulse strongly influences ultraintense interactions and hot electron generation in hollow cone an FI target. We induced a consequent preplasma copper targets measured deposition zone main pulse by imaging emitted K_{alpha} radiation. Simulation radiation hydrodynamics particle cell modeling interaction agree well...
We assess the conversion efficiency from intense picosecond laser pulses to multi-MeV ion beams for a wide range of and target parameters, using 2D kinetic particle-in-cell simulations. Scalings are addressed in quasi-one-dimensional geometry, leaving out beam divergence. Then, we study into narrow spatial band along axis flat hemispherical targets large-scale Combining these findings allows us calculate energy requirements ignition compressed ICF with an proton fast-ignition scenario.
A multifluid implicit plasma simulation code has been used to study the transport of hot electrons generated by an intense $(\ensuremath{\ge}3\ifmmode\times\else\texttimes\fi{}{10}^{18}\phantom{\rule{0ex}{0ex}}\mathrm{W}/\mathrm{cm}{}^{2})$ short-pulse 1.06 \ensuremath{\mu}m laser into targets over a broad range densities $[(0.35--200){n}_{\mathrm{crit}}]$, as arising in Fast Ignitor approach inertial confinement fusion. The most (16--250 MG) magnetic fields this interaction are traced...
In order for inertial confinement fusion (ICF) capsules to achieve high gain, they must not break up because of hydrodynamic instability, the fuel should be maintained on a low adiabat, and peak laser intensities below thresholds various plasma instabilities. this paper results two-dimensional computer calculations modeling growth instabilities slabs directly driven with are reported. direct drive succeed capsule finishes 100–300 Å, imploded an adiabat factor 3– 4 in pressure above...
We investigate the hydrodynamic response of plasma gradients during interaction with ultraintense energetic laser pulses using kinetic particle simulations. Energetic are capable compressing preformed over short times, while accelerating low-density backward. As light is absorbed on a steepened interface, hot-electron temperature and coupling efficiency drop below ponderomotive scaling we left an absorption mechanism that strongly relies electrostatic potential caused by plasma. describe...
A method for producing a self-generated magnetic focussing structure beam of laser-generated relativistic electrons using complex array resistivity gradients is proposed and demonstrated numerical simulations. The created by target consisting alternating layers different Z material. This new scheme capable effectively the fast even when source highly divergent. application this technique to cone-guided ignition inertial confinement fusion considered, it shown that may be possible deposit...
New short-pulse kilojoule, Petawatt-class lasers, which have recently come online and are coupled to large-scale, many-beam long-pulse facilities, undoubtedly serve as very exciting tools capture transformational science opportunities in high energy density physics. These lasers also happen reside a unique laser regime: high-energy (kilojoule), relatively long (multi-picosecond) pulse-lengths, large (10s of micron) focal spots, where their use driving energetic particle beams is largely...
Z-pinch implosions driven by the SATURN device [D. D. Bloomquist et al., Proceedings of 6th Institute Electrical and Electronics Engineers (IEEE) Pulsed Power Conference, Arlington, VA, edited P. J. Turchi B. H. Bernstein (IEEE, New York, 1987), p. 310] at Sandia National Laboratory are modeled with a two-dimensional radiation magnetohydrodynamic (MHD) code, showing strong growth magneto-Rayleigh–Taylor (MRT) instability. Modeling linear nonlinear development MRT modes predicts bubble-spike...
Zohar (two-dimensions, particle-in-cell) [C. K. Birdsall and A. B. Langdon, Plasma Physics via Computer Simulation (McGraw–Hill, New York, 1985)] simulations of ultra intense laser beams boring into overdense plasmas whose parameters are guided by the fast-ignitor concept radiography applications presented. Complex low frequency magnetic field structures, narrow channel formation, beam deflection all evident. Particle tracking diagnostics elucidate nature currents that produce interact with...
We investigate the hydrodynamic response of plasma gradients during interaction with ultraintense energetic laser pulses, using kinetic particle simulations. Energetic pulses are capable compressing preformed over short times while accelerating low-density backwards. As light is absorbed on a steepened interface, hot-electron temperature and coupling efficiency drop below ponderomotive scaling, we left new absorption mechanism that strongly relies electrostatic potential caused by plasma....
Abstract The interaction of petawatt (10 15 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics these relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible know fraction absorbed light f , even range unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show first time exhibits theoretical maximum minimum....
In our experiments, we irradiated solid CH targets with a 400 J, 5 ps, $3\ifmmode\times\else\texttimes\fi{}{10}^{19}{\mathrm{W}/\mathrm{c}\mathrm{m}}^{2}$ laser, and used x-ray imaging spectroscopic diagnostics to monitor the keV emission from thin Al or Au tracer layers buried within targets. The experiments were designed quantify spatial distribution of thermal electron temperature density as function layer depth; these data provide insights into behavior relativistic currents which flow...
Two-dimensional, integrated calculations of a close-coupled version the distributed radiator, heavy ion target predict gain 130 from 3.3 MJ beam energy. To achieve these results, case-to-capsule ratio was decreased by about 25% previous targets [M. Tabak and D. Callahan-Miller, Phys. Plasmas 5, 1895 (1998)]. These are robust to changes in stopping model because can be accommodated target. The capsule is also insensitive deuterium–tritium (DT) gas fill center over range that interest for...