Coherent properties of vortex Bessel-Gaussian beams propagating in the turbulent atmosphere are theoretically studied. The approach to the analysis of this problem is based on the analytical solution of the equation for the transverse second-order mutual coherence function of the optical radiation field. The behavior of coherence degree, coherence length and integral scale of coherence degree of vortex Bessel-Gaussian beams depending on parameters of a beam and characteristics of the turbulent atmosphere is particularly considered. It is shown that the coherence length, and integral scale of coherence degree of a vortex Bessel-Gaussian beam essentially inversely depend on the topological charge of a vortex beam. Thus, in process of increase in a topological charge of a vortex beam the increase in reduction of values of coherence radius and integral scale of coherence degree of a vortex Bessel-Gaussian beam becomes less. The value of the given effect also essentially depends on characteristics of the turbulent atmosphere: at weak and strong fluctuations of optical radiation the given effect is not great, it reaches a maximum in the transition region from weak to strong fluctuations of optical radiation.
V.V. Dudorov, A.S. Eremina
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: турбулентная атмосфера, скорость ветра, некогерентное изображение, turbulent atmosphere, wind velocity, incoherent image
Possibilities of the crosswind profiling along an observation path of a distant object from the analysis of distortions of atmospheric object images are studied in this work by numerical simulation. The proposed method for wind velocity determination is based on the analysis of two adjacent incoherent images and exhibit higher performance in comparison with counterparts, which is explained by the absence of accumulation of analyzed statistical characteristics. A new method for filtration of turbulent distortions of an image by their characteristic sizes is suggested with the aim of determining the wind velocity at different segments of an observation path. The work shows a possibility of determining the motion velocity under certain turbulent conditions for several (no less than three) layers of turbulent atmosphere, which are located at different positions between observed object and optical system.
S.M. Bobrovnikov1,2, E.V. Gorlov1,2, V.I. Zharkov1 1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia 2National Research Tomsk State University, 36, Lenin Avenue, Tomsk, 634050,Russia
Keywords: лидар, комбинационное рассеяние света, дистанционное обнаружение, высокоэнергетические материалы, lidar, Raman scattering, remote detection, high energetic materials
We present experimental results on the remote detection of surface traces of some high energetic materials using a Raman lidar designed on the basis of an excimer KrF laser with a narrow generation line and a multi-channel spectrum analyzer based on diffraction spectrograph and time gated CCD camera. Sensitivity of the system is evaluated for the detection range 10 m. A detection limit of 0.5 μg/cm2 is reached for the surface density of traces of nitrogen-containing chemical materials at the signal accumulation over 1000 laser pulses.
V.V. Veretennikov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: аэрозольная оптическая толщина, микроструктура аэрозоля, корреляция, регрессия, aerosol optical depth, aerosol microstructure, correlation, regression
Possibilities of estimating the microstructure parameters of atmospheric aerosol from regression equations that describe their relationships with spectral measurements of the aerosol optical depth (AOD) are considered. Special attention is given to the volume concentration, total cross section, and average radius of coarse aerosol particles. The urgency of this problem is stipulated by large errors in the retrieval of the above-indicated parameters in the case of direct АОD retrieval from measurements in an insufficiently wide spectral range. The coefficients of simple and multiple linear regressions are estimated and the results of retrieval on their basis of coarse aerosol parameters from data of solar photometry in Tomsk are presented.
V.V. Veretennikov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: аэрозольная оптическая толщина, микроструктура аэрозоля, обратные задачи, aerosol optical thickness, aerosol microstructure, inverse problems
Results of investigations of the time variability of aerosol microstructure parameters retrieved by inversion of spectral measurements of the aerosol optical depth (АОD) are presented. The input data were obtained at the IAO SB RAS using solar photometers of SP type in the observation periods 2003-2006 and 2011-2014. During the first period of measurement, the АОD was measured at 13 wavelengths in the range 0.37-4 mm. In the second observation period, the upper limit of the spectral range of measurements was 2.14 mm. The total volume of the data processed included over 7000 hourly average spectra. The geometric aerosol cross section, volume concentration, and average particle radius are analyzed.
M.Yu. Arshinov1, B.D. Belan1, N.G. Voronetskaya2, A.K. Golovko2, D.K. Davydov1, A.S. Kozlov3, G.S. Pevneva2, D.V. Simonenkov1, A.V. Fofonov1 1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia 2Institute of Petroleum Chemistry of the Siberian Branch of the RAS, 4, Academichesky ave., Tomsk, 634021, Russia 3V.V. Voevodsky Institute of Chemical Kinetics and Combustion of the Siberian Branch of the RAS, 3 Institutskaya str., 3, 630090, Novosibirsk, Russia
Keywords: атмосферный аэрозоль, состав, углеводороды, atmospheric aerosol, composition, hydrocarbons
The concentrations of normal hydrocarbons are studied on the basis of measurements in the surface air layer in different Siberian regions and in the free atmosphere over the Kara Sea water area. The total content of normal hydrocarbons in the aerosol composition is found to change from 244.56 ng/m3 in the surface air layer to 0.08 ng/m3 in the free atmosphere over the Kara Sea. Most organic compounds are from the C15H32-C22H46 range independently of the season; lighter compounds beginning from C9H20 are detected in the mid-seasons (spring and autumn); C18H38 concentration is maximal in autumn; C19H40, in spring and summer, and C20H42, in winter.
A method for calculating the optimal consumption of the resource control of perturbed dynamic systems. This method includes both normal and singular solutions. According to the method proposed the problem is subdivided into three independent tasks: 1) a consideration of the effects of perturbations on the system; 2) computation of the optimal control structure; 3) computation of the switching moments of optimal control. A consideration of the effects of perturbations on the system and transfer to a non-zero final state are reduced to the transformation of the initial and final states of the systems. The structure calculation is based on the relation between deviations in the initial conditions of the conjugate systems and deviations of the phase trajectory at the completion instant. An iterative algorithm has been developed, its characteristics being considered. The results of modeling and numerical calculations are given.
E.A. Bondarev1, A.F. Voevodin2, K.K. Argunova1, I.I. Rozhin1 1Institute of Oil and Gas Problems of Siberian Branch of Russian Academy of Sciences, Oktyabrskaya, 1, Yakutsk, Russia, 677980 2Lavrentyev Institute of Hydrodynamics, Siberian Branch of the Russian Academy of Sciences, Lavrentiev st., 15, Novosibirsk, 630090
Keywords: уравнение состояния, природный газ, гиперболические уравнения, equation of state, natural gas, hyperbolic equations
By comparison with reliable experimental data in a wide range of pressure and temperature, it has been shown that the Redlich-Kwong equation of state appropriately reflects all the characteristics of the coefficient of compressibility, the throttling factor and the normalized difference of specific isobaric and isochoric heat capacities. It has been found that this equation corresponds to the inequalities required to ensure a set of equations of gas flow in pipelines to be hyperbolic.
A.N. Kremlev
Research Institute of Applied Informatics and Mathematical Geophysics, 14 A. Nevskogo ul., Kaliningrad, 236041
Keywords: уравнение эйконала, уравнение Гамильтона-Якоби, лучевой параметр, преломление на выпуклом и вогнутом углах, время первых вступлений, аналитическое вязкое решение, головная волна, конечно-разностная схема Годунова, eikonal equation, Hamilton-Jacobi equation, ray parameter, refraction on convex and concave obtuse angle, first arrival times, analytical viscosity solution, head wave, Godunov finite difference scheme
The strict analytical solution to the eikonal equation for the plane wave refracted on convex and concave obtuse angles has been built. It has a shock line for the ray vector field and the first arrival times at the convex angle and a rarefaction cone with diffracted waves at the concave angle. This cone corresponds to the Keller diffraction cone in the geometric diffraction theory. The comparison of the first arrival times, the Hamilton-Jacoby equation times for downward waves and the conservation ray parameter equation times was made. It is shown that these times are equal only for pre-critical incident angles and are different for sub-critical angles. It is shown that the most energetic wave arrival times, which have dominant practical importance, are equal to the times calculated for the conservation ray parameter equation. The numerical algorithm proposed for these times calculation may be used for arbitrary velocity models.
