G. F. Swadling
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View article: Toward an improved nonlocal thermodynamic equilibrium model for more predictive simulations of ignition scale hohlraums
Toward an improved nonlocal thermodynamic equilibrium model for more predictive simulations of ignition scale hohlraums Open
Recently, nonlocal thermodynamic equilibrium (NLTE) modeling has been identified as the primary reason for discrepant predictions of the peak neutron production time in indirectly driven inertial confinement fusion (ICF) platforms. It has …
View article: Evaluating nonlocal heat transport in directly driven chromium spheres using x-ray spectroscopy
Evaluating nonlocal heat transport in directly driven chromium spheres using x-ray spectroscopy Open
We report on experiments investigating heat transport in laser-generated plasmas using directly driven chromium spheres. The spheres are fielded at the OMEGA laser facility and are driven with laser intensities of 5×1014Wcm−2. Plasma condi…
View article: Resolving discrepancies in bang-time predictions for indirect-drive ICF experiments on the NIF: Insights from the Build-A-Hohlraum campaign
Resolving discrepancies in bang-time predictions for indirect-drive ICF experiments on the NIF: Insights from the Build-A-Hohlraum campaign Open
This study investigated discrepancies between measured and simulated x-ray drive in Indirect-Drive Inertial Confinement Fusion (ID-ICF) hohlraums at the National Ignition Facility. Despite advances in radiation-hydrodynamic simulations, a …
View article: Key advancements toward eliminating the “drive deficit” in ICF hohlraum simulations
Key advancements toward eliminating the “drive deficit” in ICF hohlraum simulations Open
This paper, extended from a Letter [Chen et al., Phys. Rev. E 110, L013201 (2024)] published in Phys. Rev. E in 2024, presents detailed results from a set of experiments studying the x-ray drive produced in laser-heated ignition-scale hohl…
View article: Observation of ponderomotively driven bow shock using Thomson scattering
Observation of ponderomotively driven bow shock using Thomson scattering Open
High-energy speckled lasers are known to exert ponderomotive forces on a plasma. This can reduce flow transverse to the propagation of the beams. When coupled with a supersonic flow, this has been shown to lead to the formation of a shock …
View article: Resolving discrepancies in bang-time predictions for indirect-drive ICF experiments on the NIF: Insights from the Build-A-Hohlraum campaign
Resolving discrepancies in bang-time predictions for indirect-drive ICF experiments on the NIF: Insights from the Build-A-Hohlraum campaign Open
This study investigated discrepancies between measured and simulated x-ray drive in Inertial Confinement Fusion (ICF) hohlraums at the National Ignition Facility (NIF). Despite advances in radiation-hydrodynamic simulations, a consistent "…
View article: Modeling and simulations of hydrodynamic shocks in a plasma flowing across randomized ICF scale laser beams
Modeling and simulations of hydrodynamic shocks in a plasma flowing across randomized ICF scale laser beams Open
High-energy laser beams interacting with flowing plasmas can produce a plasma response that leads to deflection of the beam, beam bending. Such beams have usually a speckle structure generated by optical smoothing techniques that reduce th…
View article: <i>Ex situ</i> calibration of the scattered-light time-history diagnostic on the National Ignition Facility
<i>Ex situ</i> calibration of the scattered-light time-history diagnostic on the National Ignition Facility Open
The scattered-light time-history diagnostic (SLTD) suite measures time-resolved scattered light in three wavelength bands: stimulated Brillouin scattering (350–352 nm), stimulated Raman scattering (430–760 nm), and plasma emission at half …
View article: Diagnosing inertial confinement fusion ignition
Diagnosing inertial confinement fusion ignition Open
Fusion ignition by inertial confinement requires compression and heating of the fusion fuel to temperatures in excess of 5 keV and densities exceeding hundreds of g/cc. In August 2021, this scientific milestone was surpassed at the Nationa…
View article: Understanding the deficiency in inertial confinement fusion hohlraum x-ray flux predictions using experiments at the National Ignition Facility
Understanding the deficiency in inertial confinement fusion hohlraum x-ray flux predictions using experiments at the National Ignition Facility Open
The predicted implosion performance of deuterium-tritium fuel capsules in indirect-drive inertial confinement fusion experiments relies on precise calculations of the x-ray drive in laser-heated cavities (hohlraums). This requires accurate…
View article: A deep learning approach to fast analysis of collective Thomson scattering spectra
A deep learning approach to fast analysis of collective Thomson scattering spectra Open
Fast analysis of collective Thomson scattering ion acoustic wave features using a deep convolutional neural network model is presented. The network was trained from spectra to predict the plasma parameters, including ion velocities, popula…
View article: Shock formation in flowing plasmas by temporally and spatially smoothed laser beams
Shock formation in flowing plasmas by temporally and spatially smoothed laser beams Open
The cumulative impact of multiple laser speckles on a supersonic plasma flow across optically smoothed laser beams is investigated. The bending of laser beams caused by ponderomotive laser–plasma coupling, together with flow, leads to plas…
View article: Electron Injection via Modified Diffusive Shock Acceleration in High-Mach-number Collisionless Shocks
Electron Injection via Modified Diffusive Shock Acceleration in High-Mach-number Collisionless Shocks Open
The ability of collisionless shocks to efficiently accelerate nonthermal electrons via diffusive shock acceleration (DSA) is thought to require an injection mechanism capable of preaccelerating electrons to high enough energy where they ca…
View article: Probing local electron temperature and density inside a sheared flow stabilized Z-pinch using portable optical Thomson scattering
Probing local electron temperature and density inside a sheared flow stabilized Z-pinch using portable optical Thomson scattering Open
We report the first optical Thomson scattering measurements inside a high electron temperature (≳1 keV) and moderate electron density (mid 1016 cm−3) plasma. This diagnostic has been built to provide critical plasma parameters, such as ele…
View article: Experimental evidence of early-time saturation of the ion-Weibel instability in counterstreaming plasmas of CH, Al, and Cu
Experimental evidence of early-time saturation of the ion-Weibel instability in counterstreaming plasmas of CH, Al, and Cu Open
The collisionless ion-Weibel instability is a leading candidate mechanism for the formation of collisionless shocks in many astrophysical systems, where the typical distance between particle collisions is much larger than the system size. …
View article: Quantitative assessment of fitting errors associated with streak camera noise in Thomson scattering data analysis
Quantitative assessment of fitting errors associated with streak camera noise in Thomson scattering data analysis Open
Thomson scattering measurements in high energy density experiments are often recorded using optical streak cameras. In the low-signal regime, noise introduced by the streak camera can become an important and sometimes the dominant source o…
View article: Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent plasmas
Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent plasmas Open
In conventional gases and plasmas, it is known that heat fluxes are proportional to temperature gradients, with collisions between particles mediating energy flow from hotter to colder regions and the coefficient of thermal conduction give…
View article: Novel design for a polarizing DUV spectrometer using a Wollaston prism and its application as a diagnostic for measuring Thomson scattering data in the presence of strong self-emission backgrounds
Novel design for a polarizing DUV spectrometer using a Wollaston prism and its application as a diagnostic for measuring Thomson scattering data in the presence of strong self-emission backgrounds Open
We present a novel design for an optical spectrometer for use in ultraviolet Thomson scattering measurements of plasma parameters in high energy density (HED) inertial confinement fusion experiments on large-scale high-energy laser facilit…
View article: Characterization of thermal transport and evolution of Au plasma in ICF experiments by Thomson scattering
Characterization of thermal transport and evolution of Au plasma in ICF experiments by Thomson scattering Open
This paper demonstrates the capability of optical Thomson scattering (OTS) to measure thermal transport, and provides support to radiation hydrodynamic and kinetic simulations of electron thermal transport and plasma evolution. OTS theory …
View article: Characterization of thermal transport and evolution of Au plasma in ICFexperiments by Thomson scattering - TS data
Characterization of thermal transport and evolution of Au plasma in ICFexperiments by Thomson scattering - TS data Open
Thomson scattering data for heat transport measurements.
View article: Characterization of thermal transport and evolution of Au plasma in ICFexperiments by Thomson scattering - TS data
Characterization of thermal transport and evolution of Au plasma in ICFexperiments by Thomson scattering - TS data Open
Thomson scattering data for heat transport measurements and simulated profiles.
View article: Characterization of thermal transport and evolution of Au plasma in ICFexperiments by Thomson scattering - TS data
Characterization of thermal transport and evolution of Au plasma in ICFexperiments by Thomson scattering - TS data Open
Thomson scattering data for heat transport measurements and simulated profiles.
View article: The Scattered Light Time-history Diagnostic suite at the National Ignition Facility
The Scattered Light Time-history Diagnostic suite at the National Ignition Facility Open
The Scattered Light Time-history Diagnostic (SLTD) is being implemented at the National Ignition Facility (NIF) to greatly expand the angular coverage of absolute scattered-light measurements for direct- and indirect-drive inertial confine…
View article: Investigation of heat transport using directly driven gold spheres
Investigation of heat transport using directly driven gold spheres Open
Recently, heat transport was investigated using a directly driven beryllium sphere [Farmer et al., Phys. Plasmas 27, 082701 (2020)]. Models that overly restrict heat transport were rejected. This paper extends work to directly driven gold …
View article: FY20 LLNL Experimental Programs at Omega
FY20 LLNL Experimental Programs at Omega Open
In Fiscal Year 2020 (FY20), Lawrence Livermore National Laboratory’s (LLNL’s) High-Energy-Density Physics (HED) and Indirect Drive Inertial Confinement Fusion (ICF-ID) programs conducted numerous campaigns on the OMEGA and OMEGA-EP (EP) la…
View article: Thomson scattering Cross section Calculator
Thomson scattering Cross section Calculator Open
Code to calculate Thomson scattering cross sections.
View article: Validation of heat transport modeling using directly driven beryllium spheres
Validation of heat transport modeling using directly driven beryllium spheres Open
Recent experiments involving directly driven beryllium spheres are reported. Plasma conditions are measured using Thomson scattering with the probe beam pointed 200, 300, and 400 μm from the surface of the sphere. Laser coupling is assesse…
View article: Measurement of Kinetic-Scale Current Filamentation Dynamics and Associated Magnetic Fields in Interpenetrating Plasmas
Measurement of Kinetic-Scale Current Filamentation Dynamics and Associated Magnetic Fields in Interpenetrating Plasmas Open
We present the first local, quantitative measurements of ion current filamentation and magnetic field amplification in interpenetrating plasmas, characterizing the dynamics of the ion Weibel instability. The interaction of a pair of laser-…