A5034266392- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- Atomic and Molecular Physics
- Astro and Planetary Science
- Pulsed Power Technology Applications
- Plasma Diagnostics and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Particle Detector Development and Performance
- Laser Design and Applications
- Nuclear Physics and Applications
- Energetic Materials and Combustion
- Combustion and Detonation Processes
- Advanced X-ray Imaging Techniques
- Electrostatic Discharge in Electronics
- High-pressure geophysics and materials
- Particle accelerators and beam dynamics
- Advanced Sensor Technologies Research
- Advanced Fiber Laser Technologies
- Gas Dynamics and Kinetic Theory
- Radio Frequency Integrated Circuit Design
- Composite Structure Analysis and Optimization
- Magnetic confinement fusion research
- Gamma-ray bursts and supernovae
- Topology Optimization in Engineering
China Academy of Engineering Physics
2024
L-3 Communications (United States)
2001-2004
Maxwell Technologies (United States)
2000-2003
University of California, Irvine
1997-2003
The first observations of gaseous load implosions with over 15 MA in >110 ns on the Z generator [R. B. Spielman et al., Phys. Plasmas 5, 2105 (1998)] are reported. Starting from a diameter 8 cm, an argon double-shell pinch imploded to under 0.5 cm K-shell emission diameter. With mass 0.8 mg/cm, x-ray output reached 274±24 kJ TW peak power, 12 pulse. This record-high yield is consistent current-squared scaling predicted for “efficient” regime.
We have applied the technique of acetone laser-induced fluorescence (LIF) to measurement gas distributions from axisymmetric supersonic nozzles used produce loads for z-pinch plasma radiation sources. Typical peak particle densities are ∼1017 particles/cm3 imploded on Double-EAGLE facility. The experimental approach uses a pulsed laser (266 nm wavelength, 2.2 mJ per pulse, 5 ns pulse width, and 3×107 W/cm2 intensity) obtain snapshot along chord through center density distribution at an...
Recent observations are given for an argon double-shell gas puff imploded with up to 4 MA in 200 ns on the Double Eagle generator [G. B. Frazier et al., Digest of Technical Papers, Fourth IEEE Pulsed Power Conference (IEEE, Piscataway, NJ, 1983), p. 583]. Good K-shell x-ray output good pinch quality was observed. A novel experimental procedure used selectively seed inner or outer plenums a chlorine tracer. The tracer data provide first direct evidence that mass initially closest axis is...
We have developed a dual-plenum gas valve coupled to double shell nozzle for the generation of “shell-on-shell” loads in z-pinch plasma radiation source experiments. The density profiles nozzles been characterized with laser interferometry. This valve/nozzle combination has successfully fielded on Double-EAGLE and Saturn pulsed-power generators. design characterization shell-on-shell are presented this article.
Recently, an 8 cm diameter double-shell nozzle has produced argon Z pinches with high K-shell yields implosion time of 210 ns. To produce even longer for facilities such as Decade Quad [D. Price, et al., “Electrical and Mechanical Design the in PRS Mode,” Proceedings 12th IEEE Pulsed Power Conference, Monterey, CA, edited by C. Stallings H. Kirbie (IEEE, New York, 1999), p. 489] (9 MA short circuit current at 300 ns), a larger (12 outer diameter) was designed fabricated. During initial...
Solid-fill nozzles for long-implosion Z-pinch experiments to produce argon K-shell x rays (photon energy >3.1 keV) have been developed. With a 7 cm diam nozzle, which is appropriate 200 ns driver, stable implosions at 180 and 4 MA produced peak yields exceeding 15 kJ. As previously seen with short (∼100 ns) implosion times, the yield scales as fourth power of current, I4. Limited testing 10 >250 has also achieved implosion.
High-sensitivity interferometry measurements of initial density distributions are reviewed for a wide range gas-puff nozzles used in plasma radiation source (PRS) z -pinch experiments. Accurate gas required determining experimental load parameters, modeling implosion dynamics, understanding the properties stagnated pinch, and predicting PRS performance future For number these nozzles, simple ballistic-gas-flow model (BFM) has been to provide good physics-based analytic fits measured r ,...
Hardware and software have been developed for recording displaying accurate image spectral data produced by z-pinch plasma radiation sources at the Double-EAGLE facility Maxwell Physics International. Desktop computers are used to acquire data, analyze it, display print results. Of four charge-coupled device (CCD) systems implemented, two record x rays directly optical light emission from electron–excited phosphors. The CCD required careful shielding allow them operate in harsh radio...
Timely estimates of z-pinch plasma conditions can aid in the optimization radiation source K-shell emission. For example, a shell-on-shell argon gas puff has many parameters, such as axial density profile, inner to outer shell mass ratio, total mass, and pinch load length, which be varied on shot by basis. At Double-EAGLE facility at Maxwell Physics International, digital cameras have been implemented routinely record pinhole images, x-ray spectra, axially resolved streak images. A computer...
A series of nickel z pinch experiments was conducted at 18 MA current on the Z accelerator producing up to 13 kJ K-shell radiation 7.8 keV and above. Double-shell wire arrays were used, with diameter outer array nested structure varied from 55 70 mm. By using Cr Mn dopants in conjunction a streak spectrograph, interaction inner could be investigated. The E started slightly after lasted longer, comparable energy per atom lower power. This indicates that well mixed for most pulse, contrast...
The spatial profiles of key physical variables such as electron temperature and density are crucial in determining the overall radiating efficiency a Z pinch well emitted photon energy distribution. present work uses spatially resolved x-ray lines from shots taken on 4 MA Double EAGLE generator [C. Deeney et al., Phys. Rev. A 44, 6762 (1991)] at Maxwell Physics International to infer profiles. loads were arrays 15 wires consisting 95% Al, 5% Si, producing nearly 50 kJ K-shell radiation with...
The phenomenon of mass ejection from shocked surface is a crucial issue in high-energy density physics and shock compression science. Ejecta double-shock loaded metallic targets important some practical applications, but there are only few research types on this aspect due to experimental difficulty. We proposed new method loading based intense laser, that is, the laser injected into vacuum hohlraum generate strong radiation plasma jet simultaneously, target respectively subjected two shocks...
The Doppler broadening of ion line profiles emitted by z-pinch plasma provides information about the thermalization implosion kinetic energy and radiation efficiency pinch. Measurements these are often complicated source in instrument opacity radiation. A high resolution concave crystal spectrometer Johann geometry was used to record time averaged spectra optically thin trace elements load. An imaging slit provided radially resolved but axially spectra. measurements indicate that lower...
Theoretical studies have predicted that the disruptive role of Rayleigh-Taylor (R-T) instability on current conduction and implosion characteristics annular Z-pinch loads will be mitigated by mass accretion if uniform fill or multiple shell are used. Holographic interferometry was used to study these physical processes during phase puff-on-puff a terawatt accelerator. Both axial (r-z) density perturbation azimuthal (r-/spl theta/) filamentation modes R-T were observed. Significant ionization...
DECADE Module 2 (DM2) implodes argon gas-puffs in 200-300 ns from initial radii of 2.5-5 cm to generate K-line radiation. An important issue for these experiments is the lower-than-expected radiation associated with such large radius implosions. Preionization may improve implosion quality by improving symmetry current flow. A preionizer described based on photoionization ultraviolet (UV) illumination a flashover source. The preionization diagnosed using high-sensitivity interferometer. This...
Summary form only given, as follows. We have applied the technique of acetone laser-induced fluorescence (LIF) to measurement gas distributions from axisymmetric, supersonic nozzles used produce loads for z-pinch plasma radiation sources. Typical peak particle densities are /spl sim/1% an atmosphere at standard temperature. A pulsed laser is obtain a snapshot along chord through center density distribution 4.3 and 20.0 mm exit nozzle. find good agreement between LIF interferometer...
The Staged Z Pinch couples energy to a target plasma, dynamically in stages. present UCI experiment provides stable, multishell z pinches at 1.2 MA and 1 μs implosion time. Test-stand studies of an exploded-fiber indicate that the fiber core is not ionized, due current channeling high conductivity ablated plasma.
Summary form only given. The radial distribution of the ion density and electron temperature in a Z-pinch has been inferred by comparing measured values X-ray power ratio optically thick spectral line intensities with calculated ones for range assumed distributions. This procedure provided evidence an on-axis dip density. A complementary is described to analyze spectra obtained on DM-2 Double Eagle accelerators at Maxwell Physics International. In this case, radially resolved thin dopants...
Summary form only given, as follows. In a previous research, an azimuthally symmetric UV source was used to preionize the argon gas puffs in DM2 plasma radiation (PRS) experiment. It indicated that preionization helped improve PRS K-shell yield and reduce shot variations. also revealed issues of survivability replaceability must be addressed for such super-power generator environments. Based on evaluation preionizer, robust new preionizer has been fabricated fielded Double-EAGLE during...
Summary form only given, as follows. We have made streaked spectroscopy measurements of K-shell x-ray emission at the SNL/Albuquerque Z facility for both nested Ni wire arrays and Ar double-shell gas puffs. By doping either or puff shells with a different tracer, Cr Mn in case Cl puffs, we can determine when mass from each is radiating K-shell. In general, find that inner array starts emitting X rays first stops before outer does. This result runs counter to 1D picture which do not mix...
We have developed uniform-fill nozzles for long-implosion PRS experiments to produce argon K-shell x-rays (photon energy > 3.1 keV). With a 7 cm diameter nozzle, which is appropriate 200 ns driver, we achieved stable implosion at 180 and 4 MA with peak yields exceeding 15 kJ. As previously seen short (∼100 ns) times, the yield scales as fourth power of current, I <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> . Limited testing 10 >250...