Physical equations and calculation methods of XRL2D code, a 2D non-equilibrium radiation hydrodynamics code, are introduced. With this code, three different ALE methods are adopted to simulate hydrodynamic behavior of focus-line plasma of an Ag planar target driven by pre-main-pulse laser, which is a typical Ni-like Ag-ray laser experiment on ShenguangⅡ. The methods give similar and clear physical pictures:abundance distribution of Ni-like ion shows a shape of bow which agrees with distribution of XRL intensity in experiment. The methods are compared in detail as well.

A similarity model describing the physics of slab target X-ray lasers is constituted from the ideal hydrodynamic equations. The parameters of the plasma(e.g., temperature, density, and scale length) are predicted, which are important for the experimental design of slab target X-ray lasers. The model provides a mathematic tool for quantitatively predicting and explaining experimental results.

Based on the theoretical study of spatial coherence of laboratory x-ray lasers, a principle setup is proposed for x-ray laser holography, and corresponding theoretical simulation is performed for the recording and reconstruction of the lenseless Fourier transform hologram.

The efficiency of laser light energy absorbed by the coronal plasma of target is crucial to laser fusion. Using prepulse to irradiate target for increasing absorption efficiency of high intensity incident laser beam is considered and some theoretical simulations have been done. 1-D non-LTE radiative hydrodynamic code is used to simulate the interactions of laser beam with matter. The basic equations of this code are consisted of:the 1-D equations of radiative hydrodynamics, the average-atom population rate equations, the multigroup flux-limited diffusion equations for radiation transport, and the equations for deposition of laser light energy in plasma. The following physical processes are considered:the bremsstrahlung effect, radiative ionizations and recombinations, collisional ionizations by electrons and three-boby recombinations, collisional excitations and de-excitations by electrons, radiative line transitions and Compton scattering.A gaussian laser prepulse of wavelength 1.06μm, FWHM 600ps and peak intensity 1.5×10¹²W/cm² was used to irradiate thickness 20μm Au plate target, after 3ns a main gaussian pulsewith wavelength 1.06μm, FWHM 600ps and peak intensity 3.0×10¹⁴W/cm² irradiated the expanding Au plasma. The responces of laser-produced plasma conditions are shown. By comparison with without prepulsing, under the condition of same main incident laser pulse, the absorption efficiency is increased from 0.36 to 0.60 and the laser-x-ray conversion efficiency is increased from 0.16 to 0.25. The electron temperature of hot plasma is also higher than without prepulsing, and the x-ray spectrum which is emitted from laser-produced hot plasma is harder and more intense than without prepulsing. The responces of laser-produced plasma for Fe target with prepulsing are shown as well. The conclusion is that using prepulsing is useful way for getting high absorption laser beam.

The 1-D non-LTE radiative hydrodynamic laser irradiated code JB-19 is used to calculate the laser-produced plasma conditions of high z gold disk. Following physical processes are considered:bremsstrahlung effect, radiative ionization and recombination, collisional ionization by electrons and three-boby recombination, collisional excitation and de-excitation by electrons, radiative line emission and absorption and Compton scattering. A gaussian laser pulse with wavelength 1. 06μm, FWHM 600ps and peak intensity 3×10¹⁴W/cm² is used to irradiate thickness 20μm gold disk. The computational results for laser-produced plasma conditions and the absorption efficiency and laser-x-rays conversion efficiency for gold disk are shown.