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  • 1
    Electronic Resource
    Electronic Resource
    Asymmetry of Stark-broadened Lyman lines from laser-produced plasmas (1986)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 2196-2196 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Three significant causes of spectral line asymmetry: the ion-quadrupole interaction, the quadratic Stark effect, and fine-structure splitting, are included in the calculation of Lyman line profiles emitted by highly ionized hydrogenic radiators in a dense, hot plasma. The line asymmetries are shown to be strongly dependent on the plasma density, indicating that the asymmetry may be of use as a density diagnostic. This work was supported by Lawrence Livermore National Laboratory under sub-contract #5962705.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1138731
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  • 2
    Electronic Resource
    Electronic Resource
    Escape factors for Stark-broadened line profiles (1986)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 2196-2196 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Escape factors for upper and lower limits to the source function appropriate for spherical geometry have been evaluated using a set of Stark-broadened line profiles, computed with different approximations, for the Ly-∝ line of Ar xviii. The method used to compute the escape factors, which is based on a general formalism, can be applied to any kind of line profile and is suitable for any geometry. The escape factor is expressed as an integral over the frequency of a functional of the line profile; hence our treatment highlights its dependence on the line profile. Comparisons are made with previous calculations that used Holtsmarkian line profiles and significant differences are noted. This work has been submitted for publication to J. Phys. B (London). This work was supported by the U.S. DOE Grant No. DEA508-833PP-40177.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1139201
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  • 3
    Electronic Resource
    Electronic Resource
    Field-dependent dipole matrix elements and their application to the calculation of plasma-broadened line profiles (1988)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 1512-1514 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have computed field-dependent wavefunctions and dipole matrix elements for hydrogenic ions in the presence of a uniform electric field; we present the results for transitions connecting the ground and excited states. As an application we use these elements to compute Stark-broadened static line profiles and compare with similar ones that use field-independent matrix elements. The line-shape sensitivity to the use of field-dependent matrix elements is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140180
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  • 4
    Electronic Resource
    Electronic Resource
    X-ray diagnosis of high-density compression of Ar-filled polymer shell targets (abstract) (1988)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 1851-1851 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Time-resolved x-ray diagnosis is the only practical approach at present to examining the change of fuel and shell conditions during the final stages of compression of laser fusion targets. Time-resolved spectroscopy of lines emitted by the fuel or shell elements can provide information about the time history of the density, temperature, and integrity of the target. We report on time-integrated and time-resolved x-ray measurements of compressed polymer shell targets filled with Ar, or mixtures of Ar/Kr, directly irradiated by the 24-beam 2-kJ, UV (351-nm) OMEGA laser. These include x-ray photography, time-resolved and spaced-resolved x-ray spectroscopy, and x-ray diode measurements. Picosecond x-ray spectroscopy of the K shell emission from Ar has been studied, and detailed modeling and Spark Broadening analysis of the H-like and He-like line emission made. The results are compared with predictions of hydrodynamics code simulations of the implosions. From this analysis, a consistent history of the density and temperature of the compressed target is inferred. This work was supported by the U.S. DOE Office of Inertial Fusion under agreement No. DE-FC08-85DP40200 and the Sponsors of the Laser Fusion Feasibility Project at the Laboratory for Laser Energetics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140083
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  • 5
    Electronic Resource
    Electronic Resource
    X-ray spectroscopy of high-energy density inertial confinement fusion plasmas (1993)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 5 (1993), S. 3328-3336 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Analysis is presented of K- and L-shell spectra obtained from Ar and Xe dopants seeded into the fuel region of plastic capsules indirectly imploded using the Nova laser. Stark broadening measurements of the n=3-1 lines in H- and He-like Ar (Ar Ly-β and He-β, respectively) are used to infer fuel electron density, while spatially averaged fuel electron temperature is deduced from the ratio of the intensities of these lines. Systematic variations in Ar spectral features are observed as a function of drive conditions. A spectral postprocessing code has been developed to simulate experimental spectra by taking into account spatial gradients and line transfer effects, and shows good agreement with experimental data. It is shown that correct modeling of the x-ray emission requires a proper treatment of the coupled radiative transfer and kinetics problem. Continuum lowering effects are shown not to affect diagnostic line ratios, within the confines of a simple model. A recently developed diagnostic based on fitting measured line profiles of Ar He-β and its associated dielectronic satellites to theory is shown to provide a simultaneous measure of electron temperature and electron density. L-shell Xe spectroscopy is under development as an electron temperature and electron-density diagnostic. Density and temperature sensitive ratios of spectral features each consisting of many lines have been identified. Observed Xe spectra from imploded cores show the same qualitative behavior with temperature, as predicted by model calculations of Xe emission spectra. Stark broadening of Ne-like Xe 4-2 lines appears viable as an electron density diagnostic for Ne∼1025 cm−3 and is under continuing investigation. (Based on the invited paper 8I3 at the 1992 APS/DPP annual meeting [Bull. Am. Phys. Soc. 37, 1553 (1992)].)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.860964
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  • 6
    Electronic Resource
    Electronic Resource
    Spectroscopic analysis of Ar-doped laser-driven implosions : Proceedings of the tenth topical conference on high temperature plasma diagnostics (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 755-757 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In a series of experiments performed at the Laboratory for Laser Energetics plastic microballoons filled with DD and doped with small amounts of Ar were imploded using the Omega laser system. Time-resolved K-shell Ar spectra were simultaneously recorded using two spectrographs (SPEAXS and flat-crystal). We focus on the analysis of the He-β line and its associated Li-like satellites. The density and temperature sensitivity of this composite spectral feature has been studied previously [R. C. Mancini et al., Rev. Sci. Instrum. 63, 5119 (1992)]. Here, we use it as a diagnostic. Modeling results take into account the built-in density and temperature dependence characteristic of the level populations and broadening properties of these transitions; in addition, we also consider the effects of ion dynamics and opacity. To check the consistency of our analysis we include in the model the He-γ and Ly-β lines. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146532
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  • 7
    Electronic Resource
    Electronic Resource
    Density and temperature diagnostic based on the Ar He β line and associated Li-like satellites : Proceedings of the 9th topical conference on high temperature plasma diagnostics (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 5119-5121 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have modeled the temperature and density dependence of the Li-like satellites of the Ar He β line by performing NLTE kinetic modeling of level populations in conjunction with Stark broadening calculations. Composite line profiles are computed including resonance and satellite line transitions that have built-in the temperature and density dependence characteristic of the level populations and Stark broadening of these transitions. These synthetic spectra can be used to analyze experimental data, providing a simultaneous diagnostic of temperature and density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143458
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  • 8
    Electronic Resource
    Electronic Resource
    Analysis of absorption features in dense argon plasmas : Eighth topical conference on high−temperature plasma diagnostics (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 2738-2740 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We discuss the analysis of absorption features observed in a series of high-density implosion experiments in which Ar-filled microballoons were irradiated with high-energy laser pulses. The experimental spectrum shows the time evolution of an absorption feature in the core gas as the implosion achieves stagnation. While previous applications of absorption spectroscopy have mainly relied on estimates of the intensity of absorption features to infer plasma environmental conditions, here we propose to study quantitatively details of their shape. To this end, we have computed theoretical Stark-broadened line profiles and compared them with the experimental spectra. The temperature and density sensitivity are studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141816
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