G. S. Dunham

Oxygen Opacity Measurements at High-Energy-Density Conditions

J. E. Bailey, Daniel C. Mayes, Guillaume Loisel, Taisuke Nagayama et autres

We present the first benchmark measurements of oxygen opacity at high-energy-density, crucial for understanding stellar interiors. A 3-5-μm thick SiO_{2} sample was heated using a Z facility x-ray source, and opacity was measured in the 5-19.5 Å range with multiple spectrometers. The …

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First Measurement of Z Opacity Sample Evolution near Solar Interior Conditions Using Time-Resolved Spectroscopy

Guillaume Loisel, J. E. Bailey, Taisuke Nagayama, Stephanie B. Hansen et autres

Opacity model differences with Fe opacity measurements at high temperature (T>180 eV) and high electron density (n_{e}>3×10^{22} cm^{-3}) at nearly solar interior conditions have remained unresolved [Bailey et al., Nature 517, 56 (2015)10.1038/nature14048 and Nagayama et al., Phys. Rev. Lett. 122, 235001 …

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Sequential spectral line analysis for accurate density and temperature diagnosis of laboratory opacity measurements

Taisuke Nagayama, J. E. Bailey, Guillaume Loisel, Daniel C. Mayes et autres

The accuracy of iron opacity calculated in stellar interiors has been questioned since the discovery of the "solar problem" and the discrepancies between the measured and modeled iron opacity reported in 2015. Experimental opacity benchmarks require accurate temperature and density measurements, which …

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Sensitivity calibration of a Carestream HPX-1 image plate scanner

Antoinette Maestas, G. S. Dunham

There is a need to measure the sensitivity of the image plate scanners used to scan Z shot data. The Carestream HPX-1 image plate scanner was tested, and its performance was characterized to determine the system sensitivity in terms of signal per …

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Experimental methods to test photoionized plasma models in emission

Patricia B. Cho, Guillaume Loisel, J. E. Bailey, Taisuke Nagayama et autres

The expanding foil photoionized plasma platform was developed on the Z-machine at Sandia National Laboratories to produce terrestrial photoionized plasmas at some of the same conditions as those observed in astrophysical black hole accretion disks. The specific scientific goals of the platform …

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Platform-dependent advantages and challenges of laboratory stellar-opacity measurements

Taisuke Nagayama, Guillaume Loisel, James L. Bailey, G. S. Dunham et autres

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Erratum: “Radiation, optical, power flow, and electrical diagnostics at the Z facility: Layout and techniques utilized to operate in the harsh environment” [Rev. Sci. Instrum. 94, 031102 (2023)]

Timothy Webb, David E. Bliss, Gordon A. Chandler, Daniel H. Dolan et autres

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Development of a high performance MagLIF target platform using high aspect ratio coated liners and low-mix laser preheat

Adam J. Harvey-Thompson, Matthias Geißel, William E. Lewis, David A. Yager-Elorriaga et autres

We report on a series of Magnetized Liner Inertial Fusion (MagLIF) experiments conducted on the Z pulsed power facility that utilized high aspect ratio (ratio of outer radius to wall thickness) liners with dielectric coatings and low-mix laser preheat configurations. The liners …

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Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

H. Abu-Shawareb, Robert L. Acree, P. A. Adams, John J. Adams et autres

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light …

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Controlling morphology and improving reproducibility of magnetized liner inertial fusion experiments

David J. Ampleford, David A. Yager-Elorriaga, C. A. Jennings, Eric C. Harding et autres

X-ray imaging indicates magnetized liner inertial fusion (MagLIF) stagnation columns have a complicated quasi-helical structure with significant variations in x-ray brightness along the column. In this work, we describe MagLIF experiments aimed at controlling these stagnation structures by varying the initial liner …

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X-ray self-emission imaging with spherically bent Bragg crystals on the Z-machine

Eric C. Harding, G. K. Robertson, G. S. Dunham, M. R. Gómez et autres

An x-ray imaging scheme using spherically bent crystals was implemented on the Z-machine to image x rays emitted by the hot, dense plasma generated by a Magnetized Liner Inertial Fusion (MagLIF) target. This diagnostic relies on a spherically bent crystal to capture …

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Updates on iron opacity measurements at solar interior temperature

Taisuke Nagayama, James Bailey, Guillaume Loisel, G. S. Dunham et autres

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