A5048892311- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Laser Design and Applications
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Magnetic confinement fusion research
- Ion-surface interactions and analysis
- Laser Material Processing Techniques
- Advanced X-ray Imaging Techniques
- Quantum and electron transport phenomena
- Pulsed Power Technology Applications
- Mass Spectrometry Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- Energetic Materials and Combustion
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Particle accelerators and beam dynamics
- Quantum, superfluid, helium dynamics
- Solid State Laser Technologies
- Quantum Information and Cryptography
- Physics of Superconductivity and Magnetism
- Electron and X-Ray Spectroscopy Techniques
Lawrence Livermore National Laboratory
2015-2024
General Atomics (United States)
2003-2023
The University of Texas at Austin
2021-2023
Massachusetts Institute of Technology
2023
Rutherford Appleton Laboratory
2023
University of California, Los Angeles
2023
Florida Agricultural and Mechanical University
2023
University of Nevada, Reno
2003-2021
Stanford University
2021
SLAC National Accelerator Laboratory
2021
The laminarity of high-current multi-MeV proton beams produced by irradiating thin metallic foils with ultraintense lasers has been measured. For energies >10 MeV, the transverse and longitudinal emittance are, respectively, <0.004 mm mrad <10(-4) eV s, i.e., at least 100-fold may be as much 10(4)-fold better than conventional accelerator beams. fast acceleration being electrostatic from an initially cold surface, only collisions accelerating electrons appear to limit beam laminarity. ion...
The generation of high energy protons from the interaction a short laser pulse with dense plasma, accompanied by preformed low density has been studied particle-in-cell simulations. proton acceleration toward direction in plasma is characterized time-dependent model and peak given. effect electron recirculation on rear side sheath discussed it found that increases inverse proportion to target thickness. These results shed light dependence intensity, length, Finally optimal parameters for...
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.
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...
The evolution of laser-generated MeV, MA electron beams propagating through conductors and insulators has been studied by comparing measurement modeling the distribution MeV protons that are sheath accelerated propagated electrons. We find flow metals is uniform can be laser imprinted, whereas propagation induces spatial disruption fast Agreement found with material dependent modeling.
The comparative efficiency and beam characteristics of high-energy ions generated by high-intensity short-pulse lasers (approximately 1-6 x 10(19) W/cm2) from both the front rear surfaces thin metal foils have been measured under identical conditions. Using direct measurements nuclear activation techniques, we find that rear-surface acceleration produces higher energy particles with smaller divergence a than front-surface acceleration. Our observations are well reproduced realistic...
Experimental observation of the unidirectional motion a topological soliton driven by bi-harmonic ac force zero mean is reported. The made measuring current-voltage characteristics for fluxon trapped in an annular Josephson junction that was placed into microwave field. measured dependence velocity (rectified voltage) at dc bias versus phase shift between first and second harmonic driving qualitative agreement with theoretical expectations.
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...
In the electron-driven fast-ignition approach to inertial confinement fusion, petawatt laser pulses are required generate MeV electrons that deposit several tens of kilojoules in compressed core an imploded DT shell. We review recent progress understanding intense plasma interactions (LPI) relevant fast ignition. Increases computational and modeling capabilities, as well algorithmic developments have led enhancement our ability perform multi-dimensional particle-in-cell (PIC) simulations LPI...
Compound parabolic concentrator (CPC) targets are utilized at the National Ignition Facility Advanced Radiographic Capability (NIF-ARC) laser to enhance acceleration of electrons and production high energy photons, for durations 10 ps energies up 2.4 kJ. A large enhancement mean electron (&gt;2 ×) photon brightness (&gt;10×) is found with CPC compared flat targets. Using multiple diagnostic techniques different spatial locations scaling by gold activation data, spectra characterized...
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.
Ignition conditions in axially magnetized cylindrical targets are investigated by examining the thermal balance of assembled DT fuel configurations at stagnation. Special care is taken to adequately evaluate energy fraction 3.5 MeV alpha particles deposited cylinders. A detailed analysis ignition boundaries ρR,T parametric plane presented. It shown that magnetization allows a significant reduction ρR threshold only when condition BR ≳ 6 × 105G cm fulfilled (B magnetic field strength and R radius).
Energy relaxation of the hot electron population generated by relativistic laser pulses in overdense plasma is analyzed for densities ranging from below to 1000 times solid density. It predicted that longitudinal beam-plasma instabilities, which dominate energy transfer between electrons and at lower densities, are suppressed collisions beyond The respective roles collisional modes, i.e., direct collisions, diffusion, resistive return current heating, identified with respect transition...
A critical issue for the fast ignition of inertial fusion targets, where compressed fuel is ignited by injection an intense short laser pulse, whether hot electrons produced in interaction are energy range conducive to efficient heating core. This work presents first comprehensive two-dimensional kinetic simulation cone-guided approach ignition. Simulation results predict electron temperature be much lower than previously expected, which indicates possibility using them optimum core heating....
The heating of solid targets irradiated by 5×1020 W cm−2, 0.8 ps, 1.05 μm wavelength laser light is studied x-ray spectroscopy the K-shell emission from thin layers Ni, Mo, and V. A surface layer heated to ∼5 keV with an axial temperature gradient 0.6 scale length. Images Ni Lyα show hot region has ≤25 diameter. These data are consistent collisional particle-in-cell simulations using preformed plasma density profiles hydrodynamic modeling which that >100 G bar pressure compresses drives a...
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...
We study the interaction of intense petawatt laser pulses with overdense plasma over several picoseconds, using two- and three-dimensional kinetic particle simulations. Sustained irradiation non-diffraction-limited at relativistic intensities yields conditions that differ qualitatively from what is experimentally available today. Nonlinear saturation laser-driven density perturbations target surface causes recurrent emissions plasma, which stabilize keep absorption continuously high. This...
The effect of increasing prepulse energy levels on the spectrum and coupling into forward-going electrons is evaluated in a cone-guided fast-ignition relevant geometry using cone-wire targets irradiated with high intensity (${10}^{20}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$) laser pulse. Hot electron temperature flux are inferred from $K\ensuremath{\alpha}$ images yields hybrid particle-in-cell simulations. A two-temperature distribution hot was required to fit full profile, ratio...
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...
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...
The implosion efficiency in inertial confinement fusion depends on the degree of stagnated fuel compression, density uniformity, sphericity, and minimum residual kinetic energy achieved. Compton scattering-mediated 50--200 keV x-ray radiographs indirect-drive cryogenic implosions at National Ignition Facility capture dynamic evolution as it goes through peak revealing low-mode 3D nonuniformities thicker with lower than simulated. By differencing two taken different times during same...
Ionization dynamics of cold dense matter induced by ultrashort (&lt;100 fs) laser pulses is studied for intensities at the onset relativistic regime one-dimensional kinetic simulations. As a model we use particle-in-cell code that includes field and electron collisional ionization, as well elastic binary Coulomb collisions. examples different ionization mechanisms, give spatial temporal evolution laser-induced in helium gas solid boron targets. Special attention paid to quasi-static...