Parameters of an ion beam and characteristic features of its slowing-down in a plasma during fast ignition of an inertial fusion target

The physics of the heating of an inertial fusion target by a high-energy ion beam under the conditions of fast ignition of fusion reactions is studied theoretically. The characteristic features of the formation of the spatial distribution of the energy transferred to the plasma from a beam of ions with different initial energies, masses, and charges under fast ignition conditions are determined. The notion of the Bragg peak is extended with respect to the spatial distribution of the temperature of the ion-beam-heated medium. The parameters of the ion beams are determined with which to initiate different regimes of fast ignition of a thermonuclear fuel precompressed to a density of 300–500 g/cm³—the edge regime, in which the ignition region is formed at the outer boundary of the target, and the internal regime, in which the ignition region is formed within the target and, in particular, in its central parts.     

Current shunting and formation of stationary shock waves during electric explosions of metal wires in air

Results of experiments on the generation of shock waves during electric explosions of fine copper and tungsten wires in air are analyzed. The generation mechanism of stationary shock wave by a plasma piston formed during the shunting breakdown of the electrode gap in the course of a wire explosion is investigated. The role of structural elements of such discharges, such as the core, corona, and wire environment, is analyzed.     

Cloning,expression, isolation,and properties of thymidine kinase from herpes simplex virus type 1, strain L2

Thymidine kinase UL23 gene (EC 2.7.1.145) from the L2 acyclovir-sensitive strain of herpes simplex virus type 1 was cloned and expressed in E. coli. The enzyme was purified by chromatography to the purity of 90% according to PAG electrophoresis data. The Michaelis constants for the reactions with thymidine and acyclovir were determined. The enzyme was found to phosphorylate modified nucleosides, particularly 3′-deoxythymidine, 3′-deoxy-2′,3′-didehydrothymidine, 2′,3′-dideoxycytidine, 9-[(hydroxyethyl)methyl]guanine, E-5-(2-bromovinyl-2′-deoxyuridine, 9-(1,3-dihydroxy-2-propoxymethyl)guanine, 2′,3′-dideoxydehydrothymidine, β-L-2′,3′-dideoxy-3′-thiacytidine, and 3′-fluoro-3′-deoxythymidine. Some properties of the purified enzyme were compared with those of thymidine kinases of other herpes simplex virus strains. It was shown that acyclovir H-phosphonate inhibited the enzyme.     

Iberian origins of New World horse breeds

Fossil records, archaeological proofs, and historical documents report that horses persisted continuously in the Iberian Peninsula since the Pleistocene and were taken to the American continent (New World) in the 15th century. To investigate the variation within the mitochondrial DNA (mtDNA) control region of Iberian and New World horse breeds, to analyze their relationships, and to test the historical origin of New World horses, a total of 153 samples, representing 30 Iberian and New World breeds, were analyzed by sequencing mtDNA control region fragments. Fifty-four haplotypes were found and assigned to seven haplogroups. Reduced levels of variation found for the Menorquina, Sorraia, and Sulphur Mustang breeds are consistent with experienced bottlenecks or limited number of founders. For all diversity indices, Iberian breeds showed higher diversity values than South American and North American breeds. Although, the results show that the Iberian and New World breeds stem from multiple origins, we present a set of genetic data revealing a high frequency of Iberian haplotypes in New World breeds, which is consistent with historical documentation.     

Modeling of the composition of materials for soft X-ray sources used in research on inertial confinement fusion

A method for calculating and optimizing the composition of materials for soft X-ray sources used in research on inertial confinement fusion is described. For a target-converter, a material composition is determined with which the conversion of laser light into X radiation is highly efficient. A comparative analysis is carried out of the efficiencies of generation of soft X-ray emission in the plasmas of some composite materials of thin conductors (wires) used as loads in X-and Z-pinches. Numerical calculations of the optical plasma properties are reported whose results make it possible to judge the emissivity of plasmas of different materials. The results obtained are compared to the data from other studies.     

Crater formation in a target under the action of a high-power laser pulse

The formation of craters in targets of various materials under the action of a high-power neodymium-laser pulse at radiation intensities from 10¹⁰ to 10¹⁴ W/cm² was studied experimentally and theoretically. The interaction between the laser beam and solid targets is investigated to determine the efficiency of the ablation loading of various materials and the transformation of the laser energy into the energy of a shock wave.