The control of the deuterium–tritium (DT) fuel isotopic ratio has to ensure the best performance of the ITER thermonuclear fusion reactor. The diagnostic system described in this paper allows the ...measurement of this ratio analyzing the hydrogen isotope fluxes (performing neutral particle analysis (NPA)). The development and supply of the NPA diagnostics for ITER was delegated to the Russian Federation. The diagnostics is being developed at the Ioffe Institute. The system consists of two analyzers, viz., LENPA (Low Energy Neutral Particle Analyzer) with 10–200 keV energy range and HENPA (High Energy Neutral Particle Analyzer) with 0.1–4.0MeV energy range. Simultaneous operation of both analyzers in different energy ranges enables researchers to measure the DT fuel ratio both in the central burning plasma (thermonuclear burn zone) and at the edge as well. When developing the diagnostic complex, it was necessary to account for the impact of several factors: high levels of neutron and gamma radiation, the direct vacuum connection to the ITER vessel, implying high tritium containment, strict requirements on reliability of all units and mechanisms, and the limited space available for accommodation of the diagnostic hardware at the ITER tokamak. The paper describes the design of the diagnostic complex and the engineering solutions that make it possible to conduct measurements under tokamak reactor conditions. The proposed engineering solutions provide a safe—with respect to thermal and mechanical loads—common vacuum channel for hydrogen isotope atoms to pass to the analyzers; ensure efficient shielding of the analyzers from the ITER stray magnetic field (up to 1 kG); provide the remote control of the NPA diagnostic complex, in particular, connection/disconnection of the NPA vacuum beamline from the ITER vessel; meet the ITER radiation safety requirements; and ensure measurements of the fuel isotopic ratio under high levels of neutron and gamma radiation.
The influence of optical centers concentration profiles on thermal fields under high-power end-face diode pumping is analyzed using numerical model. It is shown that non-uniform distribution profiles ...of optical centers concentration are very promising for high average pump power laser amplifiers. The possibility of creating concentration profiles of optical centers in gradient-activated crystals with YAG matrix with a specified distribution along the growth axis of the crystal is demonstrated. A technology of growing gradient-activated single crystal involving active mirror as active element is proposed and discussed.
The results of experimental investigations of jet blowing for reducing or suppressing local flow separations from the upper surface of a model of the high-lift wing of civil aircraft at high angles ...of attack in the T-104 TsAGI subsonic wind tunnel are given with the aim to improve the aerodynamic characteristics in the landing regime. The low-intensity jets are blown from slot nozzles on the leading wing edges in the regions of its junction with the fuselage or the engine nacelle pylon. The results obtained for the baseline configuration of the aircraft model without jet blowing and for configurations with jet blowing at various angles to the upper wing surface are compared. It is shown that in all investigated variants increase in the jet blowing intensity leads to almost monotonic increase in the lifting properties of the model over the entire range of angles of attack. For the identical momentum coefficients, jet blowing in the zone of the wing-fuselage junction is most efficient.
The possibilities of using active neutral particle diagnostics for measuring local ion temperatures and isotopic ratio of deuterium-tritium plasma at the tokamak with reactor technologies are ...considered. Options for positioning the neutral particle analyzer relative to the diagnostic injector are presented. The fluxes of deuterium and tritium atoms escaping out of plasma were simulated in a wide range of plasma densities and temperatures. It is shown that the neutral particle analyzer active diagnostics will make it possible to measure the plasma parameters mentioned with the spatial and time resolutions of ~14 cm and ~0.01–0.1 s, respectively.
Holders of the active elements of a multi-disk multipass amplifier with a liquid-free closed cryogenic cooling cycle are modified. The equilibrium temperature of the active elements is experimentally ...investigated in relation to the power of diode pumping for the modified crystal holders. The dependence of the gain coefficient on the temperature of the active elements is measured. A small-signal gain of up to 1.2 is obtained in a single pass through the active element.
This paper presents data on the simultaneous and complementary observations of the gamma-ray burst (GRB) GRB 161017A for optical, X-ray, and gamma wavelengths obtained by the Russian multi-messenger ...Lomonosov space observatory and supplemented by additional data from the Swift satellite as well as the ground-based MASTER Global Robotic Net and the 10 m Gran Telescopio Canarias. Multifrequency spectra of this very powerful explosion indicate that it originated at a distance of 10 billion light years from Earth. Here, we present the results of the prompt, early, and afterglow optical observations. The light curves and spectra suggest that the prompt optical and high-energy emissions occur in the same region near the GRB source.
The concentration and sorption behavior of
Np on the bottom sediments of water bodies in the Far East region of Russia (Lake Khanka and Peter the Great Bay) were studied for the first time. The
Np ...concentrations vary from 1.06 × 10
to 4.43 × 10
mBq g
in the bottom sediments of Lake Khanka and from 1.05 × 10
to 2.52 × 10
mBq g
for Amur Bay. The experiment on the adsorption of Np on marine and lake sediment showed that it is sorbed through complexation with silicates (albite, leucite). The Np sorption isotherm on marine sediments is described by the Langmuir equation; the distribution coefficients (Kd) of Np vary from 57 to 588 mL g
. For lake sediments, the isotherm is described by the Henry equation; the Kd value reaches 935 mL g
.
A physical model of a mechanical thermal switch at cryogenic temperatures is studied. In the model, heat is transferred due to contact heat conduction in a detachable contact pair of two copper ...cylinders. A mechanical thermal switch is developed using a cryomagnetic system with a 10-T superconducting solenoid, and the values of thermal contact conductance are determined in a temperature interval of 10–160 K, including values at a magnetic field of 5 T. In an experimental temperature interval of 60–80 K, close to the phase transition of the DyAl
2
and GdNi
2
compounds, the thermal contact conductance is 2300–3300 W/(m
2
K). The effect of magnetic field of up to 5 T on thermal contact resistance is experimentally determined under vacuum conditions.
A model of the main geomagnetic field for 2020 and a model of secular field variations up to 2025 have been constructed from measurements from SWARM satellites. These models have been included in ...International Geomagnetic Reference Field model IGRF-13. The methodology for data selection and model calculation is described.
The applicability of neutral particle diagnostics for studying plasma parameters and additional methods of heating in the Tokamak with Reactor Technologies is analyzed. Options for the arrangement of ...diagnostic equipment, which includes three analyzers of charge-exchange atoms (neutral particle analyzers) for different energy ranges of recorded atomic fluxes, are given. It is shown that the diagnostic complex of analyzers makes it possible to measure the distribution functions of plasma thermal ions and to obtain information on the isotopic ratio of the main plasma ion component in the deuterium–tritium mode of facility operation. In addition, the proposed geometry of the analyzer arrangement makes it possible to measure the energy distribution of fast ions, which arise during neutral beam injection and ion cyclotron heating of plasma.
