A5045348811- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Laser-Matter Interactions and Applications
- Magnetic confinement fusion research
- Atomic and Molecular Physics
- Radiation Detection and Scintillator Technologies
- Cold Fusion and Nuclear Reactions
- Fusion materials and technologies
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Ion-surface interactions and analysis
- Combustion and Detonation Processes
- Astrophysics and Cosmic Phenomena
- Nuclear Materials and Properties
- Particle Detector Development and Performance
- Radiation Therapy and Dosimetry
- Radioactive contamination and transfer
- Plasma Diagnostics and Applications
- Nuclear physics research studies
- Nuclear reactor physics and engineering
- Diamond and Carbon-based Materials Research
Xidian University
2024
Massachusetts Institute of Technology
2014-2023
Plasma Technology (United States)
2014-2023
Fusion Academy
2013-2022
Fusion (United States)
1989-2019
University of Rochester
2008-2019
Energetics (United States)
2008-2019
Lawrence Livermore National Laboratory
2008-2019
General Atomics (United States)
2014-2019
Los Alamos National Laboratory
2014-2019
High-resolution spectrometry of charged particles from inertial-confinement-fusion (ICF) experiments has become an important method studying plasma conditions in laser-compressed capsules. In at the 60-beam OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)], utilizing capsules with D2, D3He, DT, or DTH fuel a shell plastic, glass, D2 ice, we now routinely make spectral measurements primary fusion products (p, D, T, He3, α), secondary (p), “knock-on” T) elastically...
Electromagnetic (E/B) fields generated by the interaction with plasmas of long-pulse, low-intensity laser beams relevant to inertial confinement fusion have been measured for first time using novel monoenergetic proton radiography methods. High-resolution, time-gated images a plastic foil driven 10(14) W/cm(2) implied B approximately 0.5 MG and E 1.5 x 10(8) V/m. Simulations these experiments LASNEX+LSP performed are in overall (though not exact) agreement data both field strengths spatial...
A distinctive way of quantitatively imaging inertial fusion implosions has resulted in the characterization two different types electromagnetic configurations and measurement temporal evolution capsule size areal density. Radiography with a pulsed, monoenergetic, isotropic proton source reveals field structures through deflection trajectories, densities are quantified energy lost by protons while traversing plasma. The consist (i) many radial filaments complex striations bifurcations,...
The spatial structure and temporal evolution of megagauss magnetic fields generated by interactions up to 4 laser beams with matter were studied an innovative, time-gated proton radiography method that produces images unprecedented clarity because it uses isotropic, truly monoenergetic backlighter (14.7-MeV protons from $\mathrm{D}^{3}\mathrm{He}$ nuclear fusion reactions). Quantitative field maps reveal precisely directly, for the first time, changes in topology due reconnection a...
DT neutron yield (Y(n)), ion temperature (T(i)), and down-scatter ratio (dsr) determined from measured spectra are essential metrics for diagnosing the performance of inertial confinement fusion (ICF) implosions at National Ignition Facility (NIF). A suite neutron-time-of-flight (nTOF) spectrometers a magnetic recoil spectrometer (MRS) have been implemented in different locations around NIF target chamber, providing good implosion coverage complementarity required reliable measurements Y(n),...
Measurements of x-ray-driven implosions with charged particles have resulted in the quantitative characterization critical aspects indirect-drive inertial fusion. Three types spontaneous electric fields differing strength by two orders magnitude, largest being nearly one-tenth Bohr field, were discovered time-gated proton radiographic imaging and spectrally resolved self-emission. The views spatial structure temporal evolution both laser drive a hohlraum implosion properties provide...
The observation of large, self-generated electric fields (≥10(9) V/m) in imploding capsules using proton radiography has been reported [C. K. Li, Phys. Rev. Lett. 100, 225001 (2008)]. A model pressure gradient-driven diffusion a plasma with is developed and applied to neutron yield deficits for equimolar D3He [J. R. Rygg, Plasmas 13, 052702 (2006)] (DT)3He [H. W. Herrmann, 16, 056312 (2009)] fuel mixtures Ar-doped deuterium fuels D. Lindl, 11, 339 (2004)]. observed anomalies are explained as...
The National Ignition Facility (NIF) will provide up to 1.8MJ of laser energy for imploding inertial confinement fusion (ICF) targets. Ignited NIF targets are expected produce 1019 DT neutrons. This unprecedented opportunities and challenges the use nuclear diagnostics in ICF experiments. In 2005, suite nuclear-ignition was defined they under development through collaborative efforts at several institutions. includes PROTEX copper activation primary yield measurements, a magnetic recoil...
Time-gated, monoenergetic radiography with 15-MeV protons provides unique measurements of implosion dynamics in direct-drive inertial-confinement fusion. Images obtained during acceleration, coasting, deceleration, and stagnation display a comprehensive picture spherical implosions. Critical information inferred from such images, hitherto unavailable, characterizes the spatial structure temporal evolution self-generated fields plasma areal density. Results include first observation radial...
Shock ignition is a two-step inertial confinement fusion concept where strong shock wave launched at the end of laser pulse to ignite compressed core low-velocity implosion. Initial shock-ignition technique experiments were performed OMEGA Laser Facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] using 40-μm-thick, 0.9-mm-diam, warm surrogate plastic shells filled with deuterium gas. The showed significant improvement in performance low-adiabat, implosions compared conventional...
A neutron spectrometer, called a magnetic recoil spectrometer (MRS), has been built and implemented at the OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] for absolute measurements of spectrum in range 6–30MeV, from which fuel areal density (ρR), ion temperature (Ti), yield (Yn) can be determined. The results first MRS are presented. In addition, measuring ρR National Ignition Facility (NIF) [G. H. Miller Nucl. Fusion 44, S228 (2004)] will essential assessing...
The fuel layer density of an imploding laser-driven spherical shell is inferred from framed x-ray radiographs. distribution determined by using Abel inversion to compute the radial opacity kappa observed optical depth tau. With additional assumption mass remaining fuel, absolute determined. This demonstrated on OMEGA laser system with two backlighters different mean energies that lead same independent backlighter energy.
We report on the first proton radiography of laser-irradiated hohlraums. This experiment, with vacuum gold (Au) hohlraums, resulted in observations self-generated magnetic fields peak values approximately 10;{6} G. Time-gated radiographs monoenergetic protons discrete energies (15.0 and 3.3 MeV) reveal dynamic pictures field structures plasma flow. Near end 1-ns laser drive, a stagnating Au (approximately 10 mg cm;{-3}) forms at center hohlraum. is consequence supersonic, radially directed...
The first experimental demonstration of Rayleigh-Taylor-induced magnetic fields due to the Biermann battery effect has been made. Experiments with laser-irradiated plastic foils were performed investigate these illusive using a monoenergetic proton radiography system. Path-integrated $B$ field strength measurements inferred from radiographs and found increase 10 $100\text{ }\text{ }\mathrm{T}\text{ }\ensuremath{\mu}\mathrm{m}$ during linear growth phase for $120\text{ perturbations. Proton...
Measurements of the $D(d,p)T$ ($dd$) and $T(t,2n)^{4}\mathrm{He}$ ($tt$) reaction yields have been compared with those $D(t,n)^{4}\mathrm{He}$ ($dt$) yield, using deuterium-tritium gas-filled inertial confinement fusion capsule implosions. In these experiments, carried out on OMEGA laser, absolute spectral measurements $dd$ protons $tt$ neutrons were obtained. From measurements, it was concluded that yield is anomalously low high relative to $dt$ an observation we conjecture be caused by a...
Astrophysical collisionless shocks are common in the universe, occurring supernova remnants, gamma ray bursts, and protostellar jets. They appear colliding plasma flows when mean free path for ion-ion collisions is much larger than system size. It believed that such could be mediated via electromagnetic Weibel instability astrophysical environments without pre-existing magnetic fields. Here, we present laboratory experiments using high-power lasers investigate dynamics of high-Mach-number...
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,...
The response of CR-39 track detectors to neutrons has been characterized and used measure neutron yields from implosions DD- DT-filled targets at the OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)], scaling fluence with R (the target-to-detector distance) characterize backscattered in target chamber. A Monte-Carlo code was developed predict efficiency for detecting DD neutrons, it agrees well measurements. Neutron detection efficiencies (1.1±0.2)×10−4 (6.0±0.7)×10−5...
The compression of direct-drive, spherical implosions is studied using cryogenic D2 targets on the 60-beam, 351-nm OMEGA laser with intensities ranging from approximately 3x10(14) to 1x10(15) W/cm2. hard-x-ray signal hot electrons generated by laser-plasma instabilities increases intensity, while areal density decreases. Mitigating hot-electron production, reducing intensity W/cm2, results in order 140 mg/cm2, good agreement 1D simulations. These will be considered future...
"Reduced" (i.e., simplified or approximate) ion-kinetic (RIK) models in radiation-hydrodynamic simulations permit a useful description of inertial-confinement-fusion (ICF) implosions where kinetic deviations from hydrodynamic behavior are important. For near the regime when ion mean free paths comparable to capsule size), using RIK model give detailed picture time- and space-dependent structure imploding capsules, allow an assessment relative importance various processes during implosion,...
A novel monoenergetic proton backlighter source and matched imaging detector have been utilized on the OMEGA laser system to study electric (E) magnetic (B) fields generated by laser-plasma interactions will be in future radiograph implosions high-energy density (HED) plasmas. The consists of an imploding glass microballoon with DHe3 fuel, producing 14.7MeV protons 3MeV DD that are then passed through a mesh divides into beamlets. For quantitative E+B field structure, several unique...
Direct drive implosions of targets filled with different mixtures D2 and He3 gas on the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] have shown an unexpected scaling experimental nuclear yields. At temperatures above a few electron volts, gases are fully ionized, hydrodynamically equivalent fuels ratios can be chosen to same mass density, total particle equation state. Implosions 50/50 mixture D:He3 by atom consistently result in measured yields half that...