High-explosive driven generators of cylindrical and plane shock waves in D2 and H2 were used for the generation of warm and dense strongly nonideal matter with an intense interparticle interaction ...and Fermi statistics. Highly resolved flash x-ray diagnostics were used to measure the adiabatic plasma compressibility. The thermodynamic measurements demonstrated the 20% increase of density at megabar pressure, just in the density range, where the electrical measurements indicated a sharp--5 orders of magnitude--increase of electrical conductivity due to pressure ionization in strongly coupled plasmas.
Overview of efforts in the field of fundamental and applied physics with tritium carried out with participation of RFNC-VNIIEF in 2007-2013 is made. New physical results of studying of muon-catalyzed ...fusion and neutron excess nuclei are presented; project of a new experiment on searching for a magnetic moment of neutrino using a tritium source and helium detector is discussed. Description of a tritium support testbed for a plasma focus-type neutron source with intensity of 10
13
s
-1
is given. Results of studies in the area of interaction of hydrogen isotopes with structural materials are summarized.
We draw attention to recent high-explosive (HE) experiments which provide compression of macroscopic amount of matter to high, even record, values of pressure in comparison with other HE experiments. ...The observed bounce after the compression corresponds to processes in core-collapse supernova explosions after neutrino trapping. Conditions provided in the experiments resemble those in core-collapse supernovae, permitting their use for laboratory astrophysics. A unique feature of the experiments is compression at low entropy. The values of specific entropy are close to those obtained in numerical simulations during the process of collapse in supernova explosions, and much lower than those obtained at laser ignition facilities, another type of high-compression experiment. Both in supernovae and HE experiments the bounce occurs at low entropy, so the HE experiments provide a new platform to realize some supernova collapse effects in laboratory, especially to study hydrodynamics of collapsing flows and the bounce. Due to the good resolution of diagnostics in the compression of macroscopic amounts of material with essential effects of nonideal plasma in EOS, and observed development of 3D instabilities, these experiments may serve as a useful benchmark for astrophysical hydrodynamic codes.
The article is devoted to Nikolai Bogolyubov, the outstanding scientist, one of the creators of modern nuclear weapons, Hero of Socialist Labor, academician of the Academy of Sciences of the USSR and ...the Academy of Sciences of the Ukrainian SSR, Doctor of Physical and Mathematical Sciences, Professor, Honored Science Worker of the Ukrainian SSR, winner of the Lenin Prize, two Stalin Prizes and the State Prize of the USSR. The article provides information about the family, childhood years and the stages of formation of N.N. Bogolyubov as a scientist and an organizer of science. Special attention is paid to the presentation of materials about the role and contribution of Bogolyubov to the success of the Nuclear Project.
Astronomical Roentgen Telescope – X-ray Concentrator (ART-XC) is the hard X-ray instrument with grazing incidence imaging optics on board the Spektr-Roentgen-Gamma (SRG) observatory. The SRG ...observatory is the flagship astrophysical mission of the Russian Federal Space Program, which was successively launched into orbit around the second Lagrangian point (L2) of the Earth-Sun system with a Proton rocket from the Baikonur cosmodrome on 13 July 2019. The ART-XC telescope will provide the first ever true imaging all-sky survey performed with grazing incidence optics in the 4–30 keV energy band and will obtain the deepest and sharpest map of the sky in the energy range of 4–12 keV. Observations performed during the early calibration and performance verification phase as well as during the ongoing all-sky survey that started on 12 December 2019 have demonstrated that the in-flight characteristics of the ART-XC telescope are very close to expectations based on the results of ground calibrations. Upon completion of its four-year all-sky survey, ART-XC is expected to detect approximately 5000 sources (~3000 active galactic nuclei, including heavily obscured ones, several hundred clusters of galaxies, ~1000 cataclysmic variables and other Galactic sources), and to provide a high-quality map of the Galactic background emission in the 4–12 keV energy band. ART-XC is also well suited for discovering transient X-ray sources. In this paper, we describe the telescope, the results of its ground calibrations, the major aspects of the mission, the in-flight performance of ART-XC, and the first scientific results.
A nonideal helium plasma has been compressed to a density of ρ ≈ 14 g/cm
3
at a pressure of
TPa (200 Mbar) in a spherical two-cascade device. The design of the device has been presented and the ...thermodynamic parameters of the helium plasma reached in it have been estimated. Data on the dynamics of the external and internal cascades in the device used to choose the calculation method have been obtained in a preliminary experiment with a hemispherical prototype. The experiment has been performed on the X-ray complex at the Russian Federal Nuclear Center All-Russian Research Institute of Experimental Physics, which includes BIM 234.3000 betatrons with a boundary energy of 60 MeV used in the multipulse bremsstrahlung generation regime with a multichannel optoelectronic system of recording X-ray images. A high-current linear accelerator LIU-R-T and an image detector assembly consisting of photochromic ADC screens have been used in addition to betatrons to detect the compressed shell cavity.
The quasi-isentropic compressibility of a strongly nonideal helium plasma in the pressure range 250–600 GPa is experimentally studied in devices with cylindrical geometry. The temperature at the ...front of a cylindrical shock wave in helium (
T
≈ 10 000 K) and the flight speed of the inner cascade (
W
≈ 3.5 km/s), in the cavity of which the maximum compressed plasma density is achieved, are measured. Data on the compression of a nonideal helium plasma to a density ρ ≈ 3 g/cm
3
at an approximately constant final temperature of 21000 K are obtained. The trajectories of the metallic shells compressing the plasma are detected using high-power pulsed X-ray sources with a boundary electron energy of up to 60 MeV. The helium plasma density is determined using the radii of the shells measured at the time of their “stop.” The compressed plasma pressure is obtained using gasdynamic calculations. Comparative theoretical calculations of the quasi-isentropic compression parameters have been carried out using the following two theoretical models: the traditional chemical plasma model (SAHA code) and an ab initio quantum molecular dynamics (QMD) approach. No anomaly of the experimental data in the pressure range of the plasma phase transition theoretically assumed in helium is detected.
The contribution of the USSR Academy of Sciences to the implementation of the Atomic Project is discussed. Examples of scientific, technical, and personnel support by the Academy of Sciences for work ...on atomic and hydrogen weapons in the Soviet Union are given. The outstanding contribution of scientists of the USSR Academy of Sciences to the creation of nuclear and thermonuclear weapons in our country is noted. The need for close cooperation between RAS scientists and the Rosatom State Corporation is emphasized.
We present our experimental results on the compressibility of strongly coupled (nonideal) degenerate deuterium and helium plasmas quasi-isentropically compressed to pressures
P
~ 20 TPa in devices ...with a spherical geometry. The trajectories of the plasma-compressing metallic shells were recorded with the help of powerful pulsed X-ray sources (betatrons) with a boundary electron energy of 60 MeV. A high-current accelerator with a penetrability of objects with an equivalent thickness of 250-mm of lead has been used for the first time as an X-ray source in our experiments. Plasma densities up to ρ ≈ 14 g cm
–3
were determined from the measured radius of the shell at the instant of its “stopping.” We derived the compressed-plasma pressure based on our gasdynamic computations including the real characteristics of the experimental devices.
We present data on the quasi-isentropic compressibility of a strongly coupled (nonideal) plasma of a deuterium–helium mixture in the range of pressures 150–250 GPa in devices with a cylindrical ...geometry and a new result obtained in an experiment with “pure” deuterium at a pressure ~200 GPa. The trajectory of the plasma-compressing metallic shells was recorded using powerful pulsed X-ray sources with a boundary electron energy up to 60 MeV. The densities of the plasma of deuterium and its mixture with helium were determined from the measured radii of the shells at the instant of their “stopping.” We derived the pressure of the compressed plasma based on gasdynamic computations including the real characteristics of the experimental devices. The data obtained confirm the conclusion previously reached at VNIIEF about a phase transition in the plasma of compressed deuterium in the range of pressures 150–160 GPa and suggest that this phase transition is retained in the mixture of deuterium with helium.
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