[en] The development of a set of stable implosions using indirectly driven plastic microspheres with argon (0.1 atm) doped deuterium (50 atm) has provided a unique source for testing the plasma spectroscopy of the high energy density imploded core. The core reaches electron densities of > 10²⁴ cm^-3 with temperatures of ∼ 1 keV and has been shown to be reproducible on a shot to shot basis. Moreover, it has been shown that not only the peak temperature and density are consistent, but that the temporal evolution of the mean temperature and density of the final phase of the implosion is also reproducible. These imploding cores provide a unique opportunity to test aspects of plasma spectroscopy that are difficult to study in other plasmas and to develop methods to test stable hydrodynamics. We present experimental results and discuss spectroscopic analysis algorithms to determine consistent temperature and density fits to determine gradients in the plasma

[en] The Nova laser facility has been used to produce matter in extreme conditions in the laboratory. The plasmas are produced by imploding spherical capsules filled with deuterium and trace amounts of Ar. A spectroscopic study of these indirectly driven, inertially confined plasmas provides measurements of the plasma parameters as a function of time. Multiple diagnostics measure peak n_e∼1x10²⁴ cm^-3 and T_e∼1000 eV. A series of experiments have demonstrated that the results are reliable and reproducible. These experiments are designed to produce laboratory implosions that can serve as a ''testbed'' for high energy density matter. Measuring temperature gradients are the next step so that they can become sources suitable for studying physics such as high-density plasma effects or radiative cooling. (c) 2000 The American Astronomical Society

No abstract available

[en] Coherent acoustic phonons have been observed in the X-ray diffraction of a laser-excited InSb crystal. Modeling based on time-dependent dynamical diffraction theory has allowed the extraction of fundamental constants, such as the electron-acoustic phonon coupling time. A dedicated beamline for time-resolved studies has been developed at the Advanced Light Source with special considerations toward high transmission, low scattering and a wide photon energy range. The facility combines a bend magnet beamline, time-resolved detectors and a femtosecond laser system

[en] General formulae for the applying the vertical dispersion principle in x-ray spectroscopy of multiple charged ions are summarized, the characteristics of the experimental schemes based on flat and bent crystals are discussed. The unique properties of the novel spectroscopic methods, i.e., their extremely high dispersion, high spectral and 1-D spatial resolution and good collection efficiency, make them very attractive for ultrahigh-resolution spectroscopy. The examples of successful use of the vertical dispersion modifications of the double-crystal and the Johann spectrometer in diagnostics of several types of laser-generated plasma are presented

[en] A vertical dispersion variant of the Johann spectrometer has been used to record the high-resolution X-ray spectra of the chlorine He-like resonance line group emitted from low-radiance plasma. The emission profiles were measured at two observation angles and decomposed into single spectral lines by using a fit based on the Levenberg-Marquardt algorithm. The results of computerized analysis of the one-dimensional (1-D) spatially resolved spectra were used to evaluate the distribution of the main plasma parameters. The electron temperature gradient 7.5.10⁴) eV cm^-1 was computed by modeling the measured spectra with the collisional-radiative package RATION. The blowoff maximum velocities 4.2-6.1.10⁷ cm s^-1 and the velocity gradients 0.9-1.6.10⁹ s^-1 were determined from the Doppler shifts of individual spectral lines within their different spatial extent. (author)

No abstract available

[en] The development of a set of stable implosions using indirectly driven plastic microspheres with argon (0.1 atm) doped deuterium (50 atm) has provided a unique source for testing the plasma spectroscopy of the high energy density imploded core. The core reaches electron densities of >10²⁴ cm^-3 with temperatures of ∼ 1 keV and has been shown to be reproducible on a shot to shot basis. Moreover, it has been shown that not only the peak temperature and density are consistent, but that the temporal evolution of the mean temperature and density of the final phase of the implosion is also reproducible. These imploding cores provide a unique opportunity to test aspects of plasma spectroscopy that are difficult to study in other plasmas and to develop methods to test stable hydrodynamics. We will present experimental results and discuss spectroscopic analysis algorithms to determine consistent temperature and density fits to determine gradients in the plasma

[en] The spectra of highly-charged ions produced by laser irradiation on flat targets at about 5 x 10¹⁴ Wcm^-2 are recorded in the range from 0.60 nm to 0.95 nm (6 A to 9.5 A) by means of two spectrographs (a flat ADP crystal and a Johann SiO₂ crystal spectrograph). The identification of the lines is supported by calculations of energies and transition probabilities in the relativistic parametric potential model. New identifications in several spectra of iron (Fe XXIII to Fe XXI), sodium-like strontium, Sr XXVIII, magnesium-like indium. In XXXVIII, and cobalt-like samarium, Sm XXXVI, are given. In the case of Fe XXIII, relativistic and non-relativistic (Cowan) ab initio calculations are compared. (orig.)

[en] Resonance lines of hydrogenlike aluminum ions emitted from a high-power laser-produced plasma have been recorded using a novel ultrahigh-resolution double-crystal x-ray spectrometer. The resolution provided by this instrument allows, for the first time, well resolved emitted line profiles and positions to be measured as a function of observation angle. Interpretation of the measured line shapes, positions, and intensities require simulations which include the transfer of radiation in a plasma with a large velocity gradient