A5082952625- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- Laser Design and Applications
- High-pressure geophysics and materials
- Ionosphere and magnetosphere dynamics
- Atomic and Molecular Physics
- Magnetic confinement fusion research
- Gas Dynamics and Kinetic Theory
- Advanced Fiber Laser Technologies
- Particle accelerators and beam dynamics
- Space Satellite Systems and Control
- Combustion and Detonation Processes
- Astrophysics and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Plasma Diagnostics and Applications
- Astro and Planetary Science
- Radiation Therapy and Dosimetry
- Computational Fluid Dynamics and Aerodynamics
- Dust and Plasma Wave Phenomena
- Photonic Crystal and Fiber Optics
- Spectroscopy Techniques in Biomedical and Chemical Research
- Advanced X-ray Imaging Techniques
- Nuclear Physics and Applications
- Tribology and Lubrication Engineering
Energetics (United States)
2015-2024
University of Rochester
2015-2024
Applied Energetics (United States)
2017-2023
University of California, Los Angeles
2010-2020
SLAC National Accelerator Laboratory
2020
Lawrence Livermore National Laboratory
2020
University of Michigan
2017
University of Cambridge
2012
Westwood College
2010
We show that monoenergetic ion beams can be accelerated by moderate Mach number collisionless, electrostatic shocks propagating in a long scale-length exponentially decaying plasma profile. Strong heating and density steepening produced an intense laser pulse near the critical launch such propagate extended at high velocities. The generation of beam is possible due to small constant sheath electric field associated with slowly decreasing conditions for acceleration high-quality, energetic...
The generation of a record peak-power 15 TW (45 J, 3 ps) in single CO(2) laser beam is reported. Using master oscillator-power amplifier system, it shown that up to 100 J energy can be extracted train ps pulses separated by 18 ps, characteristic time the molecule. bandwidth required for amplifying short injected pulse 2.5 atm final provided field broadening medium at intensities 140 GW/cm(2). measured saturation 120 mJ/cm(2) which confirms simultaneously from six rovibrational lines.
Multi-dimensional particle-in-cell simulations are used to study the generation of electrostatic shocks in plasma and reflection background ions produce high-quality high-energy ion beams. Electrostatic driven by interaction two plasmas with different density and/or relative drift velocity. The energy number reflected shock increase increasing ratio velocity between interacting plasmas. It is shown that intense lasers tailored near-critical allows for efficient heating electrons steepening...
Shocks act to convert incoming supersonic flows heat, and in collisionless plasmas the shock layer forms on kinetic plasma scales through collective electromagnetic effects. These shocks have been observed many space astrophysical systems [Smith 1975, Smith 1980, Burlaga 2008, Sulaiman 2015], are believed accelerate particles, including cosmic rays, extremely high energies [Kazanas 1986, Loeb 2000, Bamba 2003, Masters 2013, Ackermann 2013]. Of particular importance class of high-Mach number,...
We propose a new laser amplifier scheme utilizing stimulated Raman scattering in plasma conjunction with ``flying focus''---a chromatic focusing system combined chirped pump beam that provides spatiotemporal control over the pump's focal spot. Pump intensity isosurfaces are made to propagate at $v=\ensuremath{-}c$ so as be sync injected counterpropagating seed pulse. By setting interaction region just above ionization threshold of background gas, an wave is produced travels fixed distance...
Abstract Relativistic electron-positron plasmas are ubiquitous in extreme astrophysical environments such as black-hole and neutron-star magnetospheres, where accretion-powered jets pulsar winds expected to be enriched with pairs. Their role the dynamics of is many cases believed fundamental, but their behavior differs significantly from typical electron-ion due matter-antimatter symmetry charged components. So far, our experimental inability produce large yields positrons quasi-neutral...
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 chirped laser pulse focused by a chromatic lens exhibits dynamic, or "flying," focus in which the trajectory of peak intensity decouples from group velocity. In medium, flying can trigger an ionization front that follows this trajectory. By adjusting chirp, be made to travel at arbitrary velocity along optical axis. We present analytical calculations and simulations describing propagation pulse, self-similar form its profile, wave formation. The ability control speed and, conjunction,...
Abstract Experimental measurements using the OMEGA EP laser facility demonstrated direct acceleration (DLA) of electron beams to (505 ± 75) MeV with (140 30) nC charge from a low-density plasma target 400 J, picosecond duration pulse. Similar trends energy density are also observed in self-consistent two-dimensional particle-in-cell simulations. The intensity pulse is sufficiently large that electrons rapidly expelled along propagation axis form channel. dominant mechanism confirmed be DLA...
Collisionless shock acceleration of protons and ${\mathrm{C}}^{6+}$ ions has been achieved by the interaction a ${10}^{20}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$, $1\text{ }\ensuremath{\mu}\mathrm{m}$ laser with near-critical density plasma. Ablation initially solid target secondary allows for systematic control plasma profile. This enables production beams peaked spectra energies $10--18\text{ }\mathrm{MeV}/\mathrm{amu}$ energy spreads 10%--20% up to...
A novel diagnostic technique, angular filter refractometry (AFR), has been developed to characterize high-density, long-scale-length plasmas relevant high-energy-density physics experiments. AFR measures plasma densities up 1021 cm−3 with a 263-nm probe laser and is used study the expansion from CH foil spherical targets that are irradiated ∼9 kJ of ultraviolet (351-nm) energy in 2-ns pulse. The data elucidate temporal evolution profile for planar dependence on target radius spheres.
The 3 ps pulses are amplified to ~20 GW peak power in a TEA CO(2) laser using ac Stark broadening. Demonstration of such broadband coherent amplification 10 μm opens opportunities for powerful mid-IR source at high-repetition rate.
An advanced focusing scheme, called a “flying focus,” uses chromatic system combined with broadband laser pulse its colors arranged in time to propagate high intensity focus over distance that can be much greater than Rayleigh length while decoupling the speed at which peak propagates from group velocity. The flying generates short effective duration small diameter focal spot co- or counter-propagates along optical axis any Experiments validating concept measured subluminal (−0.09c)...
A series of experiments studying pre-plasma's effect on electron generation and transport due to a high intensity laser were conducted the OMEGA-EP facility. controlled pre-plasma was produced in front an aluminum foil target prior arrival short pulse beam. Energetic spectra characterized with magnetic bremsstrahlung spectrometers. Pre-plasma length shown have large impact temperature lower energy, ponderomotive scaling electrons. Super-ponderomotive electrons, seen shorter pulses, observed...
Collisionless shocks are ubiquitous in space and astrophysical systems, the class of supercritical is particular importance due to their role accelerating particles high energies. While these have been traditionally studied by spacecraft remote sensing observations, laboratory experiments can provide reproducible multi-dimensional datasets that a complementary understanding underlying microphysics. We present undertaken on OMEGA EP laser facilities show formation evolution high-Mach number...
The structure of a strong collisional shock front forming in plasma is directly probed for the first time laser-driven gas-jet experiments. Thomson scattering 526.5 nm probe beam was used to diagnose temperature and ion velocity distribution ($M\ensuremath{\sim}11$) propagating through low-density ($\ensuremath{\rho}\ensuremath{\sim}0.01\text{ }\text{ }\mathrm{mg}/\mathrm{cc}$) composed hydrogen. A forward-streaming population ions traveling excess observed heat slow down on an unmoving,...
In the shock ignition (SI) laser fusion scheme, hot electrons generated by spike pulse can either preheat fuel or strengthen shock, depending on electron characteristics. We conducted a planar target experiment OMEGA-EP facility and characterized temperature total energy of from kilojoule-class 100-ps infrared (IR) 1-ns ultraviolet (UV) interacting with large (Ln∼330−450 μm) (Te∼1−2 keV) coronal plasma at SI-relevant intensities (∼1016 W/cm2). The IR converts ∼2.5% into Thot∼ 60–90 keV,...
The multiterawatt (MTW) laser, built initially as the prototype front end for a petawatt laser system, is 1053 nm hybrid system with gain from optical parametric chirped-pulse amplification (OPCPA) and Nd:glass. Compressors target chambers were added, making MTW complete facility (output energy up to 120 J, pulse duration 20 fs 2.8 ns) studying high-energy-density physics developing short-pulse technologies diagnostics. Further extensions of support ultrahigh-intensity development an...
A supersonic gas-jet target platform has been activated on the OMEGA Laser System. An analytic model for gas dynamics in a nozzle was used to predict gas-plume parameters and design nozzles use laser-plasma experiments. The system analyzed with Mach-Zehnder interferometer study neutral density Thomson scattering plasma These initial measurements demonstrate capabilities of jet as future interaction science.
The material release on the side opposite to laser drive of a CH shell was probed at conditions relevant inertial confinement fusion. found expand further with longer scale length than that predicted by radiation-hydrodynamic simulations. simulations show relaxation back consistent measurements explains experimentally observed reduction in fusion implosion performance---specifically, reduced areal density peak compression.
<title>Abstract</title> Relativistic electron-positron (e<sup>±</sup>)plasmas are ubiquitous in extreme astrophysical environments such as black holes and neutron star magnetospheres, where accretion-powered jets pulsar winds expected to be enriched with pair plasmas. Their behaviour is quite different from typical electron-ion plasmas due the matter-antimatter symmetry of charged components their role dynamics compact objects believed fundamental. So far, our experimental inability produce...
This paper overviews experimental and numerical results on acceleration of narrow energy spread ion beams by an electrostatic collisionless shockwave driven 1 um (Omega EP) 10 (UCLA Neptune Laboratory) lasers in near critical density CH He plasmas, respectively. Shock waves targets produced high-energy 50 MeV protons (energy <30%) 314 C6+ ions <10%). Observation both carbon to similar velocities is consistent with reflection particles off the moving potential a shock front. For shocks CO2...
Hard x-ray measurements are used to infer production of hot electrons in laser-irradiated planar foils materials ranging from low- high-Z. The fraction laser energy converted electrons, fhot, was reduced by a factor 103 going low-Z CH high-Z Au, and electron temperatures were 40 ∼20 keV. reduction fhot correlates with steepening density gradient length-scales inferred plasma refraction measurements. Radiation hydrodynamic simulations predicted profiles reasonable agreement those Both...