We present the results of our experiments at the Luch laser facility in which the processes of the destruction of iron asteroids and cometary nuclei in space by nuclear explosions on their surface are simulated based on the principle of physical similarity. We present the results of our numerical simulations of impacts on the surface of iron objects confirming the similarity of the key processes in the full-scale and model cases. The technologies of fabricating miniature mockups with parameters close to those of iron asteroids and cometary nuclei are described. For various mini-mockups 3–12 mm in size at a laser energy from 50 to 450 J we provide an experimental estimate of the energy threshold for the undeniable destruction of mockups and investigate the parameters of their fragmentation. Conclusions about the probable results of the impact of a nuclear explosion on hazardous cosmic objects have been drawn.

We report on the results of experiments performed on the Iskra-5 laser facility for studying the effect of the polydeuteroethylene (CD 2 ) n working layer thickness on the operation parameter of an inverted-corona target. In all experiments of this series, the neutron yield at a level of 10 7 –3 × 10 8 DD neutrons per shot was detected for the total laser radiation energy supplied to the target by 12 second-harmonic beams in the range of 1.6–2.2 kJ. Using the neutron time-of-flight technique, we have detected an increase in the ion temperature from approximately 6.4 to 14 keV upon a decrease in the (CD 2 ) n layer thickness from 1 to 0.1 μm.

Process of spherical polystyrene capsules filling with hydrogen isotopes through the fill tube for the purpose of a cryogenic target building is described. The scheme of the stand for researches and a technique of carrying out of experiments is represented. Results of capsules filling and subsequent freezing for protium, deuterium and protium-deuterium mixture are shown.

Initial study of hydrogen isotopes distribution on inner surface of a hollow spherical shell under cryogenic conditions is given. Comparison of theoretical and experimental surfaces of ice layers of various hydrogen isotopes is performed.

We present the results of employing the alpha-spectrometry method to determine the characteristics of porous materials used in targets for laser plasma experiments. It is shown that the energy spectrum of alpha-particles, after their passage through porous samples, allows one to determine the distribution of their path length in the foam skeleton. We describe the procedure of deriving such a distribution, excluding both the distribution broadening due to statistical nature of the alpha-particle interaction with an atomic structure (straggling) and hardware effects. The fractal analysis of micro-images is applied to the same porous surface samples that have been studied by alpha-spectrometry. The fractal dimension and size distribution of the number of the foam skeleton grains are obtained. Using the data obtained, a distribution of the total foam skeleton thickness along a chosen direction is constructed. It roughly coincides with the path length distribution of alpha-particles within a range of larger path lengths. It is concluded that the combined use of the alpha-spectrometry method and fractal analysis of images will make it possible to determine the size distribution of foam skeleton grains (or pores). The results can be used as initial data in theoretical studies on propagation of the laser and X-ray radiation in specific porous samples.

An investigation is made of the dynamics and visible-range luminosity of the plasma cloud produced behind the front of a shock wave in air at a pressure of 1 Torr. The shock wave was produced on introducing the radiation of the twelve-channel Iskra-5 laser facility with a total energy of ∼2300 J into a hollow spherical plastic target of mass ∼10-4 g. Experimental data are compared with simulations.

Results in some directions of the target technology for research on high energy density and laser fusion at the Russian Federal Nuclear Centre-All-Russia Research Institute of Experimental Physics for the last three years are presented. The results of development of optical and X-ray methods of characterization and manufacturing techniques of targets for studying the equation-of-state at high pressures and the condensed rare gas targets for the influence of pulse-repeated laser irradiation are given.

The results of a comparative analysis of the compositions of silicon dioxide films prepared by the decomposition of tetraethoxysilane vapor in a glow discharge and the deposition of the products onto a substrate are presented. The compositions of films prepared in gas mixtures containing argon, oxygen, tetraethoxysilane vapor, and NaCl were compared using IR spectroscopy. The electric discharge was excited at a frequency of 19 kHz and in a radiofrequency range at 81.36 MHz. It was found that the additives of oxygen and sodium-containing vapors exerted a noticeable effect on the composition of the films. The compositions of the films prepared at the low-frequency and high-frequency discharge excitation were also different.

Results of experiments on the plasma-assisted fabrication of a silicon dioxide film with incorporated sodium are reported. The film was obtained via the decomposition of vaporized tetraethoxysilane and sodium compounds in a glow-discharge plasma and the deposition of the degradation products on a substrate. It is shown that this procedure makes it possible to incorporate up to 7 wt % sodium in the film composition.

The technique of argon determination in glass microspheres used in experiences on laser fusion is stated. The technique is based on registration of a spectrum of characteristic radiation of argon atoms, excited by β-radiation of tritium, contained in a target, or X-ray radiation of an external source for targets without tritium. The calculated dependencies of power of characteristic radiation on geometrical parameters of microspheres and results of measurement of various targets are submitted.

The research results of an opportunity of radiation-stimulated diffusion use for laser fusion microtargets filling with heavy gases are given, which they can not be filled with by means of usual diffusion. The theoretical estimates of quantity and character of radiation damages, their distribution in the volume of an irradiated material are made. The calculations of glass microshells argon filling process in mode of vacancy and effusive mechanisms of wall permeability are carried out. The experiments on argon filling of glass microspheres are carried out by means of diffusion with irradiation of them with electrons, protons and neutrons. It is experimentally shown that the neutron irradiation of the glass microspheres placed in the chamber with argon in the reactor IBR-2 (JINR, Dubna) and their subsequent annealing has resulted in the argon penetration into microspheres.

The results of research of properties and preparation conditions of the plasmochemical SiO2 films are submitted. These films coated various substrates (glass, metals, NaCl). Film deposition was carried out by decomposition of the tetraethoxycilane vapor by the electrical discharge with the frequency of about 18 kHz. The excessive products of decomposition were pumped out with maintenance of the tetraethoxycilane vapor and argon pressure of about 0.2 Torr. The study of element structure has shown that the film represents SixOy with x approximate to 1 and y approximate to 2 and contains an impurity of organic inclusions. Density and index of refraction of a coating are close to these parameters for glass SiO2. The form of the film surface is investigated depending on the coating conditions. Infrared spectra of absorption and Raman spectra are investigated. The results of attempts of the iodine in this film, as an impurity are given. This method is applied for preparing of the covering with uniform thickness on glass microspheres used as targets in laser fusion experiments on the installation "Iskra-5".

The first experiment results on investigation of molecular composition kinetics in D-T mixture depending on temperature by means of Raman spectroscopy are given. The D-T mixture is contained within the glass microspheres used as laser thermonuclear fusion (LTF) targets. It is experimentally shown that the isotope molecules concentrations do not change with rapid temperature alteration from 4 - 77 K to room temperature. Two suppositions can explain the results: either the equilibrium concentration establishment time was less 5 minutes or molecule concentration is equal to the high temperature equilibrium concentration regardless of microspheres temperature.

The molecular composition of plasma-chemical silicon dioxide deposited onto the surface of glass microspheres, which are used in laser fusion experiments on an Iskra-5 facility, was studied by IR spectroscopy. It was found that stoichiometric silica containing organic impurities was deposited on substrates regardless of the glow-discharge working gas composition. The microphotographs of the surface of films deposited in various gas discharge atmospheres were obtained using a JCMA-733 instrument. All films were amorphous, as found by X-ray diffraction analysis.

Laser fusion research demands microsized hollow shells with a large diameter and a thick wall. Because these geometric parameters are difficult to provide by fabrication, the wall thickness was increased by deposition of a silicon dioxide film on the outer surface of glass microspheres. The film was obtained by decomposition of tetraethoxysilane vapor in a low-frequency discharge plasma in mixtures with argon and oxygen. The thickness of coating was shown to be a linear function of the deposition time and the consumption of the precursor organoelement compound. The composition of plasma-deposited layers was studied and their density and refractive index were determined. Elemental analysis data showed that the coating comprised silicon dioxide with carbon and hydrogen impurities.

The experiments to study the indirect drive targets' dynamics in a highly symmetrical X-radiation field were performed on the ISKRA-5 facility. This paper covered the results of experiments with the targets in the form of a Cu spherical hohlraum, the internal surface of which is coated with Au, with six holes for laser radiation input. In the center of the aforementioned hohlraum, a glass capsule filled with D–T gas was placed. In several experiments, the central capsule was coated with an ablator made of plastic with a different thickness. This allowed us to perform a series of experiments in which the different compression degree of D–T fuel was achieved. The analyses of experimental results revealed good agreement between the latter and the spherically symmetrical hydrodynamic calculations.

The experiments measuring the density of DT mixture compressed in indirect drive targets (X-ray targets) were conducted on the ISKRA-5 facility. The density was determined from the line broadening of H- and He-like Ar doped in DT-gas as a diagnostic substance. A series of three experiments with the X-ray targets having different shell thickness of capsule filled with DT + Ar mixture were carried out. In two of the three experiments, radiation spectra of Ar were recorded and the density of compressed gas was determined. The analysis of the experimental results for the X-ray target with a 280-μm diameter and a 7 μm wall thickness revealed that the density of the compressed gas may be estimated as ∼1 g/cm3.