[en] Short communications only

[en] X-ray spectrum emissions from different regions in laser plasma have different lineshape due to Doppler or Stark broadening effects. These effects were analyzed in the experiment and corresponding fitting functions are structured. Through the fitting to the experimental spectrum data, the true lineshape can be obtained, so the line intensity can be precisely measured. This method can not only be applied to spectra radiated by laser plasmas, but also spectra in other wavelength

[en] The electron density profile of Mg laser plasma determined from the intensity ratio of resonance and intercombination lines of helium-like ions is presented in the direction of normal to the target surface. No obvious difference of electron density distributions was observed between spot and line focusing. The effects of satellites and opacity on determination of electron density are also discussed

[en] Spectral diagnostic technique was used to study the properties of line-shaped laser plasmas. Electron temperature and electron density profiles were deduced from the spectra obtained by a pinhole crystal spectrograph. The Stark-broadened line-wings of hydrogenic ions were used to deduce the electron density beyond the critical surface, and the results were compared with the theoretical model of planar laser-driven ablation. Time integrated properties of line-shaped laser plasma were also discussed and compared with those of spot-shaped laser plasma and the laser absorption theoretical estimations

[en] In the experiment of generating laser plasma in a line-focus system we found that the x-ray emission nonuniformity was increased rapidly after the pumping laser has been turned off. Our study indicates that radiative cooling instability is one possible reason for this x-ray emission nonuniformity

[en] Two possible designs are considered in this paper for increasing the GL value of recombining X-ray lasers. A 'fibers target' structure was proposed to get a rapid 3-dimensional adiabatic expanding at the initial state followed by a slower 2-dimensional plasma expansion. A 'hybrid model' was used to calculate the plasma behavior of the target and the results are presented. Theoretical results about X-ray pumped recombination X-ray laser are also reported

[en] A program was developed using the Marquardt algorithm method to fit the Stark-broadened line wings of hydrogenic ions, which can be conveniently used to measure electron density in laser-produced plasma. Applications of the method are illustrated using space-resolved 2p-1s resonance lines in line-shaped laser plasmas of Mg slab targets irradiated with different laser intensity. Space-resolved electron densities higher than the critical density are obtained by fitting the Stark-broadened line wings with the program

[en] A numerical method based on techniques of inverse Fourier convolution and nonlinear least square algorithm, etc., is presented for obtaining high-resolved X-ray spectra of laser plasmas, which can eliminate the line-broadening induced by radiation sources and spectrographs, and can improve the spectral resolving power of spectrographs. The code ESDAP has now been successfully applied to the analysis of spectra from line-shaped Mg and CaF2 laser plasmas

[en] Presented are time- and space-resolved investigation of recombination x-ray lasers. An improved method for gain determination was put forward, by which the laser gain of the Li-like Si 4f-3d transition at 13.0 nm was measured, which is in good agreement with theoretical simulation. Plasma parameters of electron density and temperature estimated from spectral Stark broadening and characteristic recombination time, respectively, were in qualitative agreement with the plasma conditions given by the theory for the 4f-3d gain