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On the basis of numerical simulation of optical radiation in a turbulent medium the influence of the value of the topological charge of the optical field on the beam wander and the intensity fluctuations of focused Laguerre-Gaussian beams is investigated. The beams are considered with different values of the topological charge of the complex field and the same radius of the initial aperture. The beams have different diffraction divergence which provides spatial separation of the radiation on the receiving aperture, thereby reducing the influence of different communications channels to each other during the signal demultiplexing. It was found that the beam wandering does not depend on the value of the topological charge of the complex field, and the behavior of the intensity fluctuations is determined by the mean intensity profile, which depends on the strength of the optical turbulence.

High-resolution Fourier transform spectroscopy laboratory measurements of pure water vapour absorption are performed at temperatures from -9 to 15°С in the near-IR spectral region. As the result the water vapour continuum absorption is retrieved within 1600 (6.25 μm) and 3600 cm ^{- 1} (2.7 μm) absorption bands. Spectral features of the continuum retrieved at 15°С are in good agreement with known data. It is shown that different spectral peaks of the continuum have different temperature dependencies.

This paper presents an overview of the experimental and theoretical results, which were obtained from the study the dependence of Zeeman splitting in the vibrational-rotational lines of 0-1 band of the absorption spectrum of nitric oxide molecule on the magnetic field. The experiments were performed in the laboratory of gas lasers at P.N. Lebedev Physical Institute of the Russian Academy of Science. To record the spectrum the method of laser magnetic resonance (LMR) with using continuous wave frequency-tunable CO laser has been applied. Theoretical analysis of LMR spectrograms was carried out in the laboratory of theoretical spectroscopy at V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, numerical model was developed. This model is based on the construction of the total effective Hamiltonian of the molecule including the interaction with an external magnetic field. The application of this model allowed us to simulate LMR spectra for given conditions and to describe the nonlinear dependence of the splitting of ro-vibrational energy levels on the magnetic field. The comparison of calculated and experimental LMR spectrograms demonstrated that the numerical model adequately reproduces the location of absorption peaks measured in a damped oscillating magnetic field.

Using the results of measurements of the mass concentration of the near-surface aerosol at Zvenigorod Scientific Station of the A.M. Obukhov Institute of Atmosphere Physics, Russian Academy of Sciences, the analysis of variations in the aerosol concentration with periods of more than 1 month is done. It is shown that the variations can be associated with the periodicities in the recurrences of trajectories of atmospheric transport from certain directions. Cases are considered when long-period variations of aerosol concentration are due to episodes of enhanced or reduced concentrations resulted from aerosol advection from appropriate directions. It is found in particular that the 1.5-month variations of the mass aerosol concentration in 1995 were due to the 1.5-month recurrence of the concentration maxima caused by transport from the south-east direction. The three-month periodicity of transport episodes from Baltic and North Atlantic in 2004 manifests itself through the 3-month recurrence of the aerosol concentration minima. A statistical relation of the near-surface aerosol concentration to dynamics of the Arctic upper troposphere is revealed.

The formulation of the physical optics approximation based on Maxwell's equations has been considered. The equivalence of various definitions of physical optics approximation has been shown. A detailed comparison of the three diffraction formulas corresponding to E -, M - and ( E , M )-theories of diffraction has been provided. It was found that in the case of diffraction on a hole in the flat screen, all three formulas give the same diffraction scattering cross section for the diffraction angles up to 60°. The polarizing elements of the Mueller matrix in this case diverge significantly even for the angles of 15-30°. It is also shown that in the case of diffraction on the tilted screen, the difference between E -, M - and ( E , M )-theories of diffraction may be significant. So when the screen is tilted about 80° E , M diffraction theory can be applied only to very small diffraction angle. The comparison of the results with the exact solution obtained by FDTD has confirmed that the difference between E , M - and ( E , M ) diffraction theories is not significant for the case of diffraction on the flat screen, but it is preferable to use the ( E , M ) diffraction theory for calculations.

A methodology and algorithms for measuring the light curves of spotless solar flares is proposed for study the chromospheres activity in H-alpha line. Software for a hardware system of the Baikal astrophysical observatory is developed for computer analysis of flares development using digital images of solar chromosphere.

In this paper, the feasibility of monitoring the objects located at a distance (up to 5 m) from a brightness amplifier in a monostatic laser monitor is demonstrated. The experimental study of the dependence of the quality of the obtained images on the distance between the object and the brightness amplifier is presented. It is shown that the time delay between the initial moment of the ASE pulse and the moment when the input signal is brought to the input of the brightness amplifier significantly specifies the image contrast at its output. A scheme that allows us to obtain high image contrast of objects located at a distance from the brightness amplifier is proposed.

The influence of pressure of air, nitrogen, and argon on generation of runaway electron beams in non-uniform electric field is studied. Obtained data on parameters of runaway electrons beam at pressures corresponding to the heights higher 20 km above the ocean in the Earth's atmosphere.

The article describes the integrated method and results of deformation-wave monitoring of temporal lining in rail tunneling in complex geological conditions on the south of Western Siberia. 3D geometric parameters of temporal lining are measured by laser scanning at a span of 3 months, which enables comparing actual 3D models of temporal lining and rocks in reinforced tunnel section. Based on the data obtained at various times of observation, shifting of unmarked points of temporal lining and deformation of tunnel walls and arch was determined. High density scanning allows remote identification of comparatively small zones where structure of rocks and state of lining are changed. The authors analyze seismic vibration of rocks under hammering, which shows that peak spectral densities of elastic wave in rocks are conditioned by low-frequency (pendulum) wave generated at siltstone and coal interface, and are related with dimension of joints and with mechanical properties of rocks.

The article describes engineering designs of dilatometer to measure transverse deformation in borehole subjected to internal pressure exerted through impermeable shell. The device is equipped with the robotized system for advance along the borehole without special sectional barrels. Functionality and capacities of the dilatometer are optimized for surveying in long directional drill holes in mines.