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The paper presents a semi-empirical wide-range equation of state (EOS) for platinum with account for melting, evaporation, and ionization. The equation is based on a wide spectrum of experimental and calculation data. Parameters for the EOS were adjusted using a genetic algorithm which proved to perform well for optimizations in big data processing. In the regions where no experimental data were available, we used results of first-principles and average-atom model calculations. The EOS was used to calculate the melting curve of platinum to pressures above 1 TPa, sound velocities along the Hugoniot curve, parameters of melting under shock compression, and parameters of the critical point. An improved model is proposed for the shear modulus in (V, T) coordinates and its variation along the shock adiabat is calculated.

A significant contribution to the natural gas production is delivered from massive reservoirs with bottom water of several unique fields of Western Siberia, confined to highly productive Cenomanian formation. Most of them are brownfields at low reservoir pressures. Despite the high permeability of the reservoirs, a strong heterogeneity in the distribution of reservoir pressure and elevation of the gas-water contact (GWC) is observed, which is not reproduced by full-scale flow simulation models. The purpose of this study was a comprehensive analysis of permeability data from various sources for one of such objects to explain the observed features of field development. The analysis of areal and vertical permeability distribution includes the results of well log interpretation (WLIR) by three methods in 81 wells over more than 250 m of reservoir thickness, and several tens of pressure build-up curves (PBU). The analysis made it possible to identify the main causes of the uneven distribution of pressure, GWC elevation, drainage of gas volumes associated with a multi-fold difference in the average permeability between the drilled central (dome) part of the site and on its periphery. As the gas is produced and the GWC shifts upward, the contrast in permeability of the drilled and un-drilled zones increases, and the most permeable intervals pass to the area below the GWC. It is for the first time for the long-developed highly productive gas reservoirs with bottom water in the Cenomanian formation that complex analysis of well logging data, field development control data, and 3D reservoir models has been used to justify interrelation between the inhomogeneity of gas drainage, reservoir pressure distribution and GWC advance and the distribution of permeability within the reservoir. The need for detailed geological analysis is shown for constructing a model of the reservoir properties distribution in the inter-well space to help localizing and activating the remaining gas volumes, which are greater than 440 billion m3 for the Medvezhye field alone.

This paper presents a multiphase equation of state for cerium, which includes the $\ensuremath{\gamma}$, $\ensuremath{\alpha}$, $\ensuremath{\varepsilon}$, and liquid phases. The $\ensuremath{\alpha}$ and $\ensuremath{\gamma}$ phases are described with the Aptekar-Ponyatovsky model for pseudobinary solutions, while the $\ensuremath{\varepsilon}$ and liquid phases are treated as pure phases. The Hugoniot and release isentropes are calculated for the solid $\ensuremath{\gamma}$, $\ensuremath{\alpha}$, liquid, and mixed phases. Based on the model developed, the Hugoniot does not cross the line of the $\ensuremath{\alpha}$-$\ensuremath{\varepsilon}$ transition and melting occurs directly from the $\ensuremath{\alpha}$ phase. The equation of state developed shows reasonable agreement with the static measurements, the experimentally determined phase diagram, and the shock experimental data. Cerium compresses isentropically through the $\ensuremath{\gamma}$-$\ensuremath{\alpha}$ transition as a result of cerium's abnormal compressibility in the region of the $\ensuremath{\gamma}$-$\ensuremath{\alpha}$ transition. The inclusion of the Aptekar-Ponyatovsky model assists in providing a way to handle both the abnormal compressibility and the anomalous melt boundary simultaneously. Experimentally under dynamic loading conditions, a three-wave structure is observed at stresses above the phase transition: an elastic wave, a phase transition wave (which appears as an isentropic compression wave), followed by a shock wave. For our model development we consider only the hydrostatic response and thus a two-wave structure would be anticipated. No phase precursor would be observed for melting. Sound velocity behind the shock front dramatically decreases in the region of the $\ensuremath{\gamma}$-$\ensuremath{\alpha}$ transition and smoothly varies through the region of melting.

The mechanism of high‐energy electrons formation in ultra‐high intensity laser pulse interaction with solid targets has been suggested and investigated. The relationship between kinetic energy of hot electrons generated from laser‐produced plasma and intensity of laser radiation in wide range of frequencies has been established. The phenomenon has been investigated using methods of relativistic mechanics, classical electrodynamics and plasma instabilities. The theoretical results are well verified by numerous experiments including original ones by the authors.