X‐ray spectroscopy of high‐energy density inertial confinement fusion plasmas

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 fitti...

[1]  J. Apruzese,et al.  The importance of photoexcitation to the ionization dynamics of laser-produced carbon plasmas , 1978 .

[2]  L. Suter,et al.  Line broadening of Ne-like xenon as a diagnostic for high-density implosion experiments , 1990 .

[3]  J. Kilkenny,et al.  The X-ray spectroscopic diagnosis of laser-produced plasmas, with emphasis on line broadening , 1980 .

[4]  Richard M. More,et al.  Electronic energy-levels in dense plasmas , 1982 .

[5]  Young,et al.  Time-resolved measurement of coronal temperature and line-intensity profiles in laser-produced plasmas. , 1988, Physical review letters.

[6]  Roberto Mancini,et al.  Density and temperature diagnostic based on the Ar He β line and associated Li‐like satellites , 1992 .

[7]  Chen,et al.  Independent determinations of temperature and ionization balance in a laser-produced plasma by use of L-shell x-ray spectra. , 1987, Physical review letters.

[8]  Epstein,et al.  Absorption-spectroscopy diagnosis of pusher conditions in laser-driven implosions. , 1986, Physical review. A, General physics.

[9]  R. Lee.  Fits for hydrogenic Stark‐broadened line profiles for the elements carbon to argon , 1985 .

[10]  D. Eder,et al.  The calculation of line transfer in expanding media , 1991 .

[11]  E. Campbell.  Recent results from the Nova program at LLNL , 1991 .

[12]  R. Mccrory,et al.  X-ray spectroscopy of laser imploded targets , 1981, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[13]  P. Bell,et al.  High Z x-ray spectroscopy of laser-imploded capsules , 1990 .

[14]  J. Apruzese,et al.  Direct solution of the equation of transfer using frequency- and angle-averaged photon escape probabilities. Interim report , 1979 .

[15]  J. Apruzese,et al.  Influence of broadband photocoupling on K-shell excitation in aluminum , 1980 .

[16]  Richard Lee,et al.  Spectra—A model for K-shell spectroscopy☆ , 1984 .

[17]  R. Lee.  Plasma line shapes for selected transitions in hydrogen-, helium- and lithium-like ions , 1988 .

[18]  Griem,et al.  Stark-profile calculations for resonance lines of heliumlike argon in dense plasmas. , 1990, Physical review. A, Atomic, molecular, and optical physics.

[19]  A. Hauer,et al.  Spectroscopic measurement of high-density CO/sub 2/-laser-driven implosion , 1980 .

[20]  Hans R. Griem,et al.  Plasma spectroscopy in inertial confinement fusion and soft x-ray laser research , 1992 .

[21]  Bradley,et al.  Time-resolved spectroscopic measurements of high density in Ar-filled microballoon implosions. , 1989, Physical review letters.

[22]  Keane,et al.  X-ray spectroscopic measurements of high densities and temperatures from indirectly driven inertial confinement fusion capsules. , 1993, Physical review letters.

[23]  Hooper,et al.  Calculation of spectral line profiles of multielectron emitters in plasmas. , 1988, Physical review. A, General physics.

[24]  Hammel.  K- and L-shell x-ray spectroscopy of indirectly driven implosions , 1992 .

[25]  R. D. Cowan,et al.  Observation of new lines of Xe xliv, xlv, xlvi, and xlvii in the range 2.5–3.0 Å from laser-imploded targets , 1981 .

[26]  J. Apruzese,et al.  Collisional-radiative-equilibrium spectroscopic diagnosis of a compressed, optically thick neon plasma , 1981 .

[27]  M. Rosen,et al.  Theory and design of soft x-ray laser experiments at the Lawrence Livermore National Laboratory , 1989 .

[28]  Talin,et al.  Model for the line shapes of complex ions in hot and dense plasmas. , 1990, Physical review. A, Atomic, molecular, and optical physics.

[29]  Iglesias,et al.  Ion-dynamic effects on the line shapes of hydrogenic emitters in plasmas. , 1986, Physical review. A, General physics.