A5075263755- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Plasma Diagnostics and Applications
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Particle accelerators and beam dynamics
- Atomic and Molecular Physics
- High-pressure geophysics and materials
- Astro and Planetary Science
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- Magnetic Field Sensors Techniques
- Laser Design and Applications
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ion-surface interactions and analysis
- Metal and Thin Film Mechanics
- Atomic and Subatomic Physics Research
- Mass Spectrometry Techniques and Applications
- Geomagnetism and Paleomagnetism Studies
- Gamma-ray bursts and supernovae
- Diamond and Carbon-based Materials Research
- Fluid Dynamics and Turbulent Flows
- Characterization and Applications of Magnetic Nanoparticles
Optical Sciences (United States)
2016-2024
University of Michigan–Ann Arbor
2015-2024
Energetics (United States)
2011-2021
University of Rochester
2010-2021
Lawrence Livermore National Laboratory
2013-2021
Columbia University
2021
Applied Mathematics (United States)
2021
University of California, San Francisco
2021
Princeton University
2000-2019
Princeton Plasma Physics Laboratory
2001-2019
Enhancement of the ion temperature and fusion yield has been observed in magnetized laser-driven inertial confinement implosions on OMEGA Laser Facility. A spherical CH target with a 10 atm D2 gas fill was imploded polar-drive configuration. magnetic field 80 kG embedded subsequently trapped compressed by imploding conductive plasma. As result hot-spot magnetization, electron radial heat losses were suppressed neutron enhanced 15% 30%, respectively.
Filamentation due to the growth of a Weibel-type instability was observed in interaction pair counterstreaming, ablatively driven plasma flows, supersonic, collisionless regime relevant astrophysical shocks. The flows were created by irradiating opposing plastic (CH) foils with 1.8 kJ, 2-ns laser pulses on OMEGA EP Laser System. Ultrafast laser-driven proton radiography used image Weibel-generated electromagnetic fields. experimental observations are good agreement analytical theory Weibel...
Experiments applying laser-driven magnetic-flux compression to inertial confinement fusion (ICF) targets enhance the implosion performance are described. Spherical plastic (CH) filled with 10 atm of deuterium gas were imploded by OMEGA Laser, compare Phys. Plasmas 18, 056703 or 056309. Before being imploded, immersed in an 80-kG magnetic seed field. Upon laser irradiation, high velocities and ionization target fill trapped field inside capsule, it was amplified tens megagauss through flux...
Observations of magnetic reconnection between colliding plumes magnetized laser-produced plasma are presented. Two counterpropagating flows created by irradiating oppositely placed plastic (CH) targets with 1.8-kJ, 2-ns laser beams on the Omega EP Laser System. The interaction region is prefilled a low-density background and an externally applied field, imposed perpendicular to flow, initialized X-type null point geometry B=0 at midplane B=8 T targets. counterflowing sweep up compress field...
A series of Omega experiments have produced and characterized high velocity counter-streaming plasma flows relevant for the creation collisionless shocks. Single double CH2 foils been irradiated with a laser intensity ∼ 1016 W/cm2. The ablated was 4 mm from foil surface using Thomson scattering. peak flow 2000 km/s, an electron temperature 110 eV, ion 30 density 1018 cm−3 were measured in single configuration. Significant increases temperatures seen geometry. conditions used to calculate...
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,...
Nonuniformities seeded by both long- and short-wavelength laser perturbations can grow via Rayleigh-Taylor (RT) instability in direct-drive inertial confinement fusion, leading to performance reduction low-adiabat implosions. To mitigate the effect of imprinting on target performance, spherical RT experiments have been performed OMEGA using Si- or Ge-doped plastic targets a cone-in-shell configuration. Compared pure target, radiation preheating from these high-$Z$ dopants...
Magnetic fields generated by a current flowing through U-shaped coil connecting two copper foils were measured using ultrafast proton radiography. Two ∼1.25 kJ, 1-ns laser pulses propagated entrance holes in the front foil and focused to back with an intensity of ∼3 × 1016 W/cm2. The intense laser-solid interaction induced high voltage between large coil. data show ∼40–50 T magnetic at center ∼3–4 ns after irradiation. experiments provide significant insight for future target designs that...
The local electron energy flux produced by magnetic fluctuations has been measured directly in the MST reversed field pinch (over radial range r/a>0.75).The flux, electrons traveling parallel to a fluctuating magentic field, is obtained from correlation between heat and field. fluctuation induced large (100 kW/${\mathrm{cm}}^{2}$) ``core'' (r/a0.85) small (10--30 edge.
To support direct-drive inertial confinement fusion experiments at the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 43, 2841 (2004)] in its indirect-drive beam configuration, polar-direct-drive (PDD) concept [S. Skupsky et al., Phys. Plasmas 11, 2763 has been proposed. PDD geometry requires direct-drive–specific smoothing, phase plates, repointing NIF beams toward equator to ensure symmetric target irradiation. First study energetics preheat...
An upgrade of the pulsed magnetic field generator magneto-inertial fusion electrical discharge system [O. Gotchev et al., Rev. Sci. Instrum. 80, 043504 (2009)] is described. The device used to study magnetized high-energy-density plasma and capable producing a tens tesla in volume few cubic centimeters. created by discharging high-voltage capacitor through small wire-wound coil. coil current pulse has duration about 1 μs peak value 40 kA. Compared original, updated version larger energy...
Using two-dimensional particle-in-cell simulations, we examine how an externally applied strong magnetic field impacts proton acceleration in laser-irradiated solid-density targets. We find that a kT-level external can sufficiently inhibit transverse transport of hot electrons flat target. While the electron heating by laser remains mostly unaffected, reduced during leads to enhancement maximum energies and overall number energetic protons. The resulting beam is much better collimated...
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...
We present the first laboratory observations of time-resolved electron and ion velocity distributions in magnetized collisionless shock precursors. Thomson scattering a probe laser beam was used to observe interaction laser-driven, supersonic piston plasma expanding through an ambient external magnetic field. From Thomson-scattered spectra we measure profiles density, temperature, flow speed, as well spatially resolved fields from proton radiography. direct evidence coupling between plasmas,...
We describe here efforts to create and study magnetized electron–positron pair plasmas, the existence of which in astrophysical environments is well-established. Laboratory incarnations such systems are becoming ever more possible due novel approaches techniques plasma, beam laser physics. Traditional plasmas studied date, both nature laboratory, exhibit a host different wave types, many generically unstable evolve into turbulence or violent instabilities. This complexity instability these...
According to the Lipid World hypothesis, life on Earth originated with emergence of amphiphilic assemblies in form lipid micelles and vesicles (liposomes). However, mechanism appearance information molecules (ribozymes/RNA) accompanying that process, considered obligatory for Darwinian evolution, is unclear. We propose a novel scenario self-sustained evolution liposomes driven by ever-present natural phenomena: solar UV radiation, day/night cycle, gravity, formation an aqueous media. The...
Electron current fluctuations are measured with an electrostatic energy analyzer at the edge of MST reversed-field pinch plasma. The radial flux fast electrons ($E>{T}_{\mathrm{ea}}$) due to parallel streaming along a fluctuating magnetic field is determined locally by measuring correlated product $〈{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{J}}_{e}{\stackrel{\ifmmode \~{}\fi{}}{B}}_{r}〉$. Particle transport small just inside last closed surface...
Reduction of core-resonant m=1 magnetic fluctuations and improved confinement in the Madison Symmetric Torus [Dexter et al., Fusion Technol. 19, 131 (1991)] reversed-field pinch have been routinely achieved through control surface poloidal electric field, but it is now known that has limited part by edge-resonant m=0 fluctuations. Now, refined field control, plus toroidal possible to reduce simultaneously This allowed high-energy runaway electrons, possibly indicative flux-surface...
A Thomson parabola ion spectrometer has been designed for use at the Multiterawatt (MTW) laser facility Laboratory Laser Energetics (LLE) University of Rochester. This device uses parallel electric and magnetic fields to deflect particles a given mass-to-charge ratio onto parabolic curves on detector plane. Once calibrated, position ions plane can be used determine particle energy. The dispersion both was measured using monoenergetic proton alpha beams from SUNY Geneseo 1.7 MV tandem...
A narrowband x ray imager for the Cu Kα line at ∼8 keV using a spherically bent quartz crystal has been implemented on OMEGA EP laser University of Rochester. The is cut along 2131 (211) planes 2d spacing 0.3082 nm, resulting in Bragg angle 88.7°, very close to normal incidence. An optical system used remotely align spherical without breaking vacuum target chamber. images show high signal-to-background ratio typically >100:1 with energies ≥1 kJ 10-ps pulse duration and spatial...
Complementary measurements of ion energy distributions in a magnetically confined high-temperature plasma show that magnetic reconnection results both anisotropic heating and the generation suprathermal ions. The anisotropy, observed ${\mathrm{C}}^{+6}$ impurity ions, is such temperature perpendicular to field larger than parallel field. tail appears majority distribution well described by power law energies 10 times thermal energy. These observations may offer insight into energization process.