The results of unique experiments on synchronous recording of oscillations of earth’s surface with three laser interferometers–deformographs spaced at a distance of 6740 km, obtained during ...2016–2020, are considered: two 100-m laser deformographs (Fryazino, Moscow oblast) and one 18-meter (Karymshina site, Kamchatka krai). It is shown that frequency-stabilized and thermocontrolled lasers, as well as systems for registering shifts of the compensation and modulation type interferogram provide an absolute instrumental resolution of 0.1–0.01 nm.
An extraordinary phenomenon of generation of coupled types of oscillations with a transverse field distribution corresponding to the ТЕМ
pq
eigenmodes with different pairs of indices
p
and
q
in the ...main laser cavity and in an external cavity has been experimentally detected. The excitation of coupled modes depends on the configuration and tuning of partial cavities. To solve the system of integral equations for a three-mirror cavity with mismatched spherical mirrors in the quasioptical approximation, it has been proposed to use modified boundary conditions including the coupling coefficients for eigenmodes in partial cavities.
This paper reports results from observations of broadband geophysical processes using laser interferometer strainmeters and special acoustic instruments. We demonstrate examples of synchronous ...recordings of earth strain variations and geoacoustic oscillations of the ground surface in Kamchatka and in the Moscow Region, as well as results from a parallel analysis of these data, showing that the method proposed here can be used to separate local and global disturbances in these processes.
The results of original experiments performed with a ground-based geophysical laser interferometer and a GPS-based satellite ionospheric profilometer are given. Synchronous growth was recorded for ...deformations of the Earth’s surface and variations in the atmospheric pressure and in the level of spatiotemporal modifications of the electron content within the ionospheric
F
2 layer with characteristic space scales of 10
2
–10
3
km and periods of 10
2
–10
3
s. The relationship between the revealed phenomena and the Earth’s seismic activity is analyzed.
The dependences of geometric characteristics of single tracks obtained by laser deposition of austenitic steel powder on the shift of the laser beam focus and the distance from the nozzle to the ...substrate at different values of mass flow and scanning speed are investigated. It is shown that the characteristic value of the track height decreases from 900 to 700 microns with a decrease in the beam size by half at a powder flow rate of 8.4 g/min and a speed of 350 mm/min, decreases from 1100 to 900 microns at a flow rate of 15.6 g/min, and increases by 30-50% with an increase in flow rate by 2.3 times. The ratio of height to width (shape factor) decreases with the growth of the scanning speed from about 0.7 to 0.4 at a flow rate of 15.6 g/min and to 0.25 at a flow rate of 8.5 g/min. Process performance scaling parameters are defined. The results obtained make it possible to optimize the technological parameters of the laser metal deposition process.
The results of investigation of the laser-interferometer electromagnetic system are presented by the example of the analysis of a three-mirror optical resonator as the simplest model of a laser ...connected to an unmatched load. Integral equations describing the electromagnetic field in a three-mirror resonator with cylindrical mirrors are analyzed. The results obtained are verified by the numerical simulation of the behavior of eigenfrequencies for several simplest designs of a three-mirror laser resonator.
The results of analysis of the motion of an elementary fragment of an elastic deforming body (geoblock) have shown that description of the geoblock by combined temporal and spatial derivatives and ...instrumental monitoring with the movement sensors (seismiographs) and strain sensors (deformographs) are the most acceptable and informative methods.
The work is devoted to the analysis of the influence of poloidal current induced in a tokamak vacuum chamber due to change of paramagnetic plasma properties as a result of thermal quench on the ...magnitude and distribution of electromagnetic forces in a vacuum chamber. The work was performed numerically using the plasma-physics code DINA for conditions of major disruption in the plasma of ITER and T-15MD. A comparison is made of the electromagnetic effect obtained from the toroidal and poloidal currents induced in the vacuum chamber as a result of thermal quench with estimates of the electromagnetic forces due to only toroidal currents. It is shown that the integral radial component of the electromagnetic force in the elements of the vacuum chamber when the poloidal current is taken into account can be much lower than in the case of only the toroidal current induced in the chamber. The paper presents a model for calculating the poloidal current induced in a vacuum chamber first used in the DINA code.
This article is devoted to the development of a software and computing system for calculating the evolution of nominal currents and voltages in the coils of the poloidal magnetic system in order to ...ensure the equilibrium of the plasma of the T-15 tokamak in a given discharge scenario. The obtained evolutions of currents and voltages are necessary for the subsequent construction of the system of magnetic control of the current, shape, and position of the plasma during the discharge scenario. The physical parameters of the discharge and the required evolution of the plasma boundary during the discharge process are set using the graphical interface. The software package is developed on the basis of the DINA plasma physics code within the Matlab-Simulink system. Examples of using the graphical interface as well as the simulation results of the ohmic scenario with a plasma current of 2 MA are presented.
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