[en] An experiment of direct-drive cylindrical target compression is carried out using the eight laser beams of Shenguang-Ⅱ laser facility with the spots defocused to 200 μm. A clear flow diagram of cylindrical target implosion is obtained with Mo backlight driven by the 9th laser beam and Kirkpatrick-Baez microscopy. Experimental result shows that, for the cylindrical target with an outer diameter of 260 μm, a compressed density of up to 120 times the initial density is obtained, which is between the densities of electron production area and energy deposition area. Experiments of electron beam transport and energy deposition in this compressed cylindrical target could be carried out once the Shenguang-Ⅱ ps laser beam is available. (authors)

[en] The principles and characteristics of point-projection radiography were studied through static imaging experiments, using laser-driven about 4.8 keV Ti plasma X-ray source. The application of point-projection to dynamic diagnosis was then developed, and an experimental platform was accomplished with about 4.8 keV photon energy, about 100 ps time resolution and about 10 μm spatial resolution. A series of experimental results from this platform were introduced, including those on hydrodynamic instability, laser-accelerated plasma jet and compression characters of materials. (authors)

[en] A line velocity interferometer for any reflector has been implemented at the Shenguang-II laser facility. This instrument is the primary diagnostic for a variety of experiments involving laser-driven shock-wave propagation,materials characterization experiments and shock timing experiments. It measures velocities of interfaces, free surfaces and shock fronts traveling through transparent media. It can measure shock breakout time at temporal resolutions as low as 20 ps, and spatial resolution 10 μm. Experiments were carried out on the Shenguang-II laser facility and high quality interference images were obtained. (authors)

[en] The attenuation factor or quality factor (Q-factor or Q) has been used to measure the energy attenuation of seismic waves propagating in underground media. Many methods are used to estimate the Q-factor. We propose a method to calculate the Q-factor based on the prestack Q-factor inversion and the generalized S-transform. The proposed method specifies a standard primary wavelet and calculates the cumulative Q-factors; then, it finds the interlaminar Q-factors using the relation between Q and offset (QVO) and the Dix formula. The proposed method is alternative to methods that calculate interlaminar Q-factors after horizon picking. Because the frequency spectrum of each horizon can be extracted continuously on a 2D time–frequency spectrum, the method is called the continuous spectral ratio slope (CSRS) method. Compared with the other Q-inversion methods, the method offers nearly effortless computations and stability, and has mathematical and physical significance. We use numerical modeling to verify the feasibility of the method and apply it to real data from an oilfield in Ahdeb, Iraq. The results suggest that the resolution and spatial stability of the Q-profile are optimal and contain abundant interlaminar information that is extremely helpful in making lithology and fluid predictions.

[en] Directly driven ablative Rayleigh—Taylor (R—T) instability of modulated CH targets was studied using the face-on X-ray radiography on the Shen-Guang II device. We obtained temporal evolution images of the R—T instability perturbation. The R—T instability growth factor has been obtained by using the methods of fast Fourier transform and seeking the difference of light intensity between the peak and the valley of the targets. Through comparison with the the theoretical simulation, we found that the experimental data had a good agreement with the theoretical simulation results before 1.8 ns, and was lower than the theoretical simulation results after that

[en] This paper presents a theoretical analysis of the dynamics of spherical metallic particles in electrostatic separators/sizers (ESSs). A computational algorithm is employed to depict the cylinder-type electrode arrangements applied in some electrostatic processes generating non-uniform electric fields. The ESS consists of a pair of conducting cylinders. The upper cylinder is energized by HVdc, while the lower one is grounded and mounted horizontally on a revolvable axis. The aim of this paper is to present a new electrode configuration and demonstrate the usefulness of numerical techniques for the evaluation of the particle's motion. A computer program was employed for analysing the behavior of spherical particles in a two-dimensional electrode arrangement that models the actual electric field configuration of cylinder-type electrostatic separators/sizers. The analysis is needed for the development of any new application of this cylinder-type electrode arrangement as an electrostatic separation method. The results reveal that the particle's motion depends on its radius and density and amplitude of the applied voltage. The actual granular mixtures with different specific mass and radius could be separated applying this cylinder-type electrostatic separation method; the lift voltage is an important parameter for separation. With a program for two-dimensional analysis of the electric field, the computational procedure presented in this paper could be employed for any particle shapes

[en] Liquid hydrogen and deuterium have abundant electrical and optical properties at high pressure. A simple model to calculate the conductivity of low-Z materials was constructed. Combining the model with experiment, this paper introduces the study of the ionization and conductivity of liquid deuterium at around 70 GPa. The results show that, deuterium at this range of pressure has an ionization about 0.067%, conductivity about 2.87 × 10⁵(W·m)^-1, which means the shocked deuterium reaches a conducting state with characteristic of metallic fluid. Apparently, the transition from the insulating molecular state to metallic state of deuterium begins at a lower pressure. (authors)

[en] Measurement of shock temperature under high temperature and high pressure is an essential part of equations of state(EOS) research. This paper introduces a temperature diagnosis system for laser-driven shock wave experiment on the basis of SG-Ⅱ high-power laser facility. The system comprised the streaked optical pyrometer (SOP) which is high time-resolved and the spectral resolved SOP (SSOP). The VISAR system was added to measure emissivity. The on-line calibration system of temperature measurement was established simultaneously using a NIST traceable standard lamp. High time-resolved signal images of the high temperature radiation spectrum were obtained through experiments driven by high power laser on aluminum using the diagnosis system. The shock temperature of aluminum was obtained according to gray body radiation theoretical model. The measured temperature was 2.95 eV, which was close to Hugoniot temperature in SESAME library at the same shock wave velocity. The experiment result indicates that the temperature measurement system used in the experiment can diagnose the shock temperature of metallic materials effectively. (authors)

[en] Based on the traditional analysis method and sample preparation device for silicon isotopic compositions by BrF₅, some improvement was made to optimize the analysis method and the sample preparation device. The improved sample preparation device includes 12 sets of independent units which have enhanced the preparation efficiency by simultaneously preparing, separating, purifying and collecting the sample. The national standard material GBW04421, quartz, and siliceous rock samples were used as the reference to test the improved device for the preparation, and analysis of silicon isotopic compositions. The analytical accuracy is 0.08‰, 0.07‰ and 0.08‰, respectively, which are less than 0.1‰. The average value of the standard material is -0.04‰, which is in good agreement with the recommended data -0.02‰. The analytical accuracy and value of standard material suggested that the improved preparation device and method is suitable for the analysis of silicon isotopic compositions. (authors)

[en] The linear conversion from the slow wave to the fast wave in the lower hybrid range of frequencies is analyzed numerically by using the set of field equations describing waves in a cold plane-stratified plasma. The equations are solved as a two-point boundary value problem, where the polarizations of each mode are set consistently in the boundary conditions. The scattering coefficients and the field patterns are obtained for various density profiles. It is shown that, for large density scale length, the results agree well with the traditional cognitions. In contrast, the reflected component and the probable transmitted-converted component from the conversion region, which are neglected in the usual calculations, become significant when the scale length is smaller than the wavelength of the mode. The inclusion of these new components will improve the accuracy of the simulated propagation and deposition for the injected rf power when the conversion process is involved within a sharp-varying density profile. Meanwhile, the accessibility of the incident slow wave for the low frequency case is also affected by the scale length of the density profile