Emission and transport characteristics of sub-keV x rays in laser-produced gold plasmas are investigated. Absolute x-ray spectra under three different experimental conditions have been measured with high spectral resolution to study dependences of x-ray emission on laser incidence angles, irradiation intensity, and thickness of a foil target. Simulations by a one-dimensional hydrodynamic code, which incorporates a detailed atomic physics, replicate quite well the general x-ray emission features obtained in the experiments. There remain, however, discrepancies in some details of spectral shapes, notably in the range between 0.5 and 0.9 keV. It is also shown that the transport of radiation heat wave deduced from x-ray emissions at the front and the rear sides of a thin gold foil may be interpreted by the self-similar solutions presented by Pakula and Sigel [Phys. Fluids. 28, 232 (1985); 29, 1340 (E) (1986)] with an approximated gold opacity under local thermodynamic equilibrium.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics