Space and time resolved spectroscopy of laser-produced plasmas: A study of density-sensitive x-ray transitions in helium-like and neon-like ions
The determination of level populations and detailed population mechanisms in dense plasmas has become an increasingly important problem in atomic physics. In this work, the density variation of line intensities and level populations in aluminum K-shell and molybdenum and silver L-shell emission spectra have been measured from high-powered, laser-produced plasmas. For each case, the density dependence of the observed line emission is due to the effect of high frequency electron-ion collisions on metastable levels. The density dependent line intensities vary greatly in laser-produced plasmas and can be used to extract detailed information concerning the population kinetics and level populations of the ions. The laser-plasmas had to be fully characterized in order to clearly compare the observed density dependence with atomic theory predictions. This has been achieved through the combined use of new diagnostic instruments and microdot targets which provided simultaneously space, time, and spectrally resolved data. The plasma temperatures were determined from the slope of the hydrogen-like recombination continuum. The time resolved electron density profiles were measured using multiple frame holographic interferometry. Thus, the density dependence of K-shell spectral lines could be clearly examined, independent of assumptions concerning the dynamics of the plasma. In aluminum, the electron density dependence of various helium-like line intensity ratios were measured. Standard collisional radiative equilibrium models fail to account for the observed density dependence measured for the ''He/sub ..cap alpha..//IC'' ratio. Instead, a quasi-steady state atomic model based on a purely recombining plasma is shown to accurately predict the measured density dependence. This same recombining plasma calculation successfully models the density dependence of the high-n ''He/sub ..gamma..//He/sub ..beta../'' and ''He/sub delta//He/sub ..beta../'' helium-like resonance line intensity ratios.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6682739
- Report Number(s):
- UCRL-53887; ON: DE89002928
- Resource Relation:
- Other Information: Thesis (Ph.D.). Portions of this document are illegible in microfiche products. Thesis. Submitted to the Univ. of California, Davis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALUMINIUM IONS
TRANSITION RADIATION
LASER-PRODUCED PLASMA
X-RAY SPECTROSCOPY
MOLYBDENUM IONS
SILVER IONS
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELECTRON-ION COLLISIONS
EMISSION SPECTRA
IONIZATION
K SHELL
L SHELL
PLASMA DIAGNOSTICS
SPATIAL RESOLUTION
TEMPERATURE DEPENDENCE
TIME RESOLUTION
CHARGED PARTICLES
COLLISIONS
ELECTROMAGNETIC RADIATION
ELECTRON COLLISIONS
ELECTRONIC STRUCTURE
ION COLLISIONS
IONS
PLASMA
RADIATIONS
RESOLUTION
SPECTRA
SPECTROSCOPY
TIMING PROPERTIES
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory
640304 - Atomic
Molecular & Chemical Physics- Collision Phenomena
700101 - Fusion Energy- Plasma Research- Confinement
Heating
& Production