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For microparticles, the intensity of spontaneous scattering is directly proportional to the volume. However, model calculations show that when the particle dimension parameter increases in the region 0.5

The software complex for automation of processing the results of the experiments on sensing of high-level clouds with the high-altitude polarization lidar developed at National Research Tomsk State University is described. The software performs the following operations: preliminary processing and visualizing experimental data; calculating optical and geometrical characteristics of the observed aerosol layers; downloading meteorological data corresponding to the place, date, and time of the lidar experiment; as well as forming summary report on the performed processing.

Sun trackers are widely used to investigate scattering and absorption of solar radiation in the Earth׳s atmosphere. We present a method for optimization of the optical altazimuth sun tracker model with output radiation direction aligned with the axis of a stationary spectrometer. The method solves the problem of stability loss in tracker pointing at the Sun near the zenith. An optimal method for tracker calibration at the measurement site is proposed in the present work. A method of moving calibration is suggested for mobile applications in the presence of large temperature differences and errors in the alignment of the optical system of the tracker.

We have developed ellipsometry lidar and measured aerosol and ice-cloud characteristics. To measure a full normalized backscattering phase matrix (NBSPM) composed of nine elements, we have designed an optical system with three kinds of transmission and three kinds of reception, composed of λ/2 waveplate, λ/4 waveplate and empty optic. To find systematic optical errors, we used clean day middle-altitude (4-6km) lidar signals for which the aerosol’s concentration was small and its orientation chaotic. After calibrating our lidar system, we have calculated NBSPM elements scattered from an aerosol and from an ice cloud. In the case of an aerosol, we found that the off-diagonal values m 12 ,...,m 34 of the NBSPM are smaller than those for a cirrus cloud. Also, the off-diagonal values of the NBSPM from a cirrus cloud depend on atmospheric conditions.

A high-current electron-beam accelerator for pumping of a Xe2 lamp was developed. It is intended for injection of an electron beam into cylindrical gas cavity (diameter of 400 mm, length of 1600 mm, and the absolute pressure up to 3 bars). Two electron diodes in parallel are used in the accelerator. Each diode is connected to a linear transformer driver with vacuum insulation of a secondary turn. The next parameters of the accelerator have been obtained: diode voltage — 550–600 kV, diode current — 276–230 kA, current rise time — 160 ns, maximum power of the electron beam — 130 GW, pulse width on half maximum — 160 ns, electron beam energy at power level not less than half of maximum value — 20 kJ. The total energy of electrons, which pass through a 40 µm Ti foil into the Xe cell, is 8–9 kJ in the 150–160 ns pulse (full width at half maximum) mean specific power of energy input into gas cavity is about 330 kW/cm3. Design of the accelerator and test results are presented and discussed in this paper.

A scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS) was held in the Conference Hall of the P N Lebedev Physical Institute, RAS on November 26, 2008. The session was dedicated to the 100th anniversary of the birth of Sergei Mikhailovich Rytov. The following reports were presented at the session: (1) Gulyaev Yu V (V A Kotel'nikov Institute of Radioengineering and Electronics, RAS, Moscow) "Sergei Mikhailovich Rytov (Opening address)"; (2) Barabanenkov Yu N (V A Kotel'nikov Institute of Radioengineering and Electronics, RAS, Moscow) "Asymptotic limit of the radiative transfer theory in problems of multiple wave scattering in randomly inhomogeneous media"; (3) Kaplan A E, Volkov S N (Johns Hopkins University, Baltimore, USA) "Local fields in nanolattices of strongly interacting atoms: nanostrata, giant resonances, 'magic numbers', and optical bistability"; (4) Klyatskin V I (A M Obukhov Institute of Atmospheric Physics, RAS, Moscow) "Modern methods for the statistical description of dynamical stochastic systems"; (5) Dolin L S (Institute of Applied Physics, RAS, Nizhny Novgorod) "Development of the radiative transfer theory as applied to instrumental imaging in turbid media". An abridge version of the reports is given below. • Sergei Mikhailovich Rytov (Opening address), Yu V Gulyaev Physics-Uspekhi, 2009, Volume 52, Number 5, Pages 499–502 • Asymptotic limit of the radiative transfer theory in problems of multiple wave scattering in randomly inhomogeneous media, Yu N Barabanenkov Physics-Uspekhi, 2009, Volume 52, Number 5, Pages 502–506 • Local fields in the nanolattices of strongly interacting atoms: nanostrata, giant resonances, 'magic numbers', and optical bistability, A E Kaplan, S N Volkov Physics-Uspekhi, 2009, Volume 52, Number 5, Pages 506–514 • Modern methods for the statistical description of dynamical stochastic systems, V I Klyatskin Physics-Uspekhi, 2009, Volume 52, Number 5, Pages 514–519 • Development of the radiative transfer theory as applied to instrumental imaging in turbid media, L S Dolin Physics-Uspekhi, 2009, Volume 52, Number 5, Pages 519–526

Methodology for determination of the optical and geometric characteristics of clouds is described. Problems of processing data obtained in experiments on polarization laser sensing of the atmosphere are discussed. Technique for reduction of the phase matrices of cirrus obtained with the high-altitude polarization lidar developed at National Research Tomsk State University to the symmetry plane affixed to the preferred orientation of ice crystals in cirrus is described. The experimental data are compared with the data of numerical modeling of phase matrices in the physical optics approximation and meteorological conditions over the lidar at cirrus altitudes. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

In this paper we present results of investigation of the main optical properties of East Asian clouds with a ground-based polarization lidar placed in Daejeon, Republic of Korea. Asian dust is located in elevated layers of the atmosphere in spring, travels long distances, and causes significant damage to ecology. We present backscattering matrices of clouds obtained from polarimetric remote measurements which comprise information on the scattering and absorption properties of cloud particles, their morphology, and spatial orientation. Theory of our applied lidar polarization experiment is presented in terms of the instrumental vectors of a transmitter and a receiver. Methods of solving linear and nonlinear systems of equations comprising echo signals are considered. Some numerical and measurement results are presented to illustrate the efficiency and versatility of the method of estimating the cloud parameters.

This article describes S-band sources of high-power microwave (HPM) pulses: a resonant backward wave oscillator (BWO) producing ∼5-GW, 100-J pulses, based on the SINUS-7 electron accelerator, and a double-section vircator with a peak power of ∼1 GW and a pulse width of 20–50 ns, powered from either the SINUS-7 accelerator or the MARINA inductive-store pulse driver with a fuse opening switch.

Primary storages based on a linear transformer scheme were developed long ago. In this scheme, the secondary turn only has to be insulated from the high output voltage. Seven years ago at the High Current Electronics Institute (HCEI) a primary storage based on a linear transformer scheme and called the Linear Transformer Driver (LTD) stage was designed. In LTD stages, the primary turn, the storage capacitors with the switches, the core, and the outer conductor of the secondary turn are integrated into the stage cavity representing one separate building block of the primary storage. The body of the LTD cavity keeps ground potential during the shot allowing us to assemble them in series or in parallel depending on load requirements. Such flexibility of the storage structure and high output power of the LTD stages allows us to replace for some applications the traditional water line technology with LTD-based primary storages that are connected directly to the load (Direct Drive Scheme—DDS). In this article, we present the design of several LTD stages developed at HCEI and give examples of high-power energy storages produced by using the LTD technology.

The design and results of tests of a vacuum feedthrough insulator for a pulsed electron accelerator with a voltage of ∼1 MV, a current of ∼20 kA, and a half-height voltage-pulse duration of ≥ 400 ns are presented. A method for distributing the voltage over the sections of the insulator due to an electron emission from specially created surfaces is proposed.

This paper describes an S-band vircator system with electron beam premodulation, built on the base of the MARINA compact high-voltage pulser with inductive energy storage. The peak microwave output was /spl sim/1 GW with /spl sim/5% power efficiency and 50-ns full-width at half-maximum. The microwave frequency was constant during the pulse as determined by the resonator. Substantial spontaneous shortening of the microwave pulse was observed. Possible mechanisms for this phenomenon are discussed and supported by three-dimensional KARAT simulations.

Experimental results of polarization laser sensing of cirrus with anomalous backscattering are presented. The technique of determining the optical and geometrical characteristics of clouds is described. Experimental data are compared with the meteorological conditions at altitudes of cirrus above the lidar location and with the results of numerical modeling of phase matrices in the approximation of physical optics. The recurrence frequency of meteorological characteristics of “mirror” cirrus is estimated.

We present an approach for improving the accuracy of T-matrix calculation of particles with point-group symmetries that eliminates from consideration some elements of the T matrix with low accuracy. A high accuracy approach (HAA) is suggested based on symmetry related comparative analysis of the accuracy rating of evaluation of surface integrals by the extended boundary condition method (EBCM). The symmetry relation for elements of the T matrix is a consequence of the general symmetry relation for particles with point-group symmetries. A simple comparative accuracy criterion composed of matrix norms r c ( Q ) = ∥ R g Q ∥ ⋅ ∥ Q − 1 ∥ is suggested, where Q and RgQ are matrices computed with evaluation of surface integrals by the EBCM. An example of practical HAA application is given and results of numerical modeling of light scattering on finite polyhedral prisms are analyzed.

We predict nanoscale local-field patterns in self-interacting 1-D and 2-D lattices of two-level atoms. They result in giant size-related resonances, low-intensity optical bistability, and self-induced cancellation of resonant local-field suppression.

The relation between the orientation of particles in ice-crystal clouds and backscattering phase matrices (BSPMs) is considered. Parameters characterizing the predominant orientation of particles in the azimuthal direction and in the horizontal position are presented. The parameters are expressed through BSPM elements. A technique for measuring BSPM elements with lidar is described. Examples of some measurements are presented along with a statistical generalization of the results from more than 400 BSPM measurements. It is found that the orientation of coarse particles with large diameters in an azimuthal direction and in a horizontal position is more probable than in a random direction. However, the orientation of large particles is often masked by small particles that are not subject to the effect of orienting factors. Thus the mean parameters characterizing the state of orientation of particles in clouds as a whole correspond to weak orientation. It is supposed that the orientation of particles in the azimuthal direction is caused by wind-velocity pulsations.

Tagging Russian texts of the XIXth century has been evaluated. The causes have been determined why some words turned out to be unknown to the tagger, i.e. remained without lemmas and grammatical features. The investigation showed that the main reasons of the existence of the unknown words were as follows: 1) incompleteness of the tagger dictionary, particularly in the XIXth century lexical stock; 2) failure to tag the word-formative derivates; 3) problems with some inflexion models of Old Russian; 4) insufficiency of graphemic analysis; 5) inability of taggers to process multiwords. The results obtained provide a baseline to improve premorphological processing of Russian texts and to work out the more sophisticated approaches to morphological analysis.

Remote lidar sensing in the photon-counting mode is now the commonly accepted method for studying atmospheric processes in the lower and free atmosphere. However, when processing signals obtained from lidar measurements, investigators necessarily face the problem of achieving accuracy in reconstructing the atmospheric parameters despite the presence of inhomogeneous noise in the measured signals. We propose an optimal method of linear regression (OMLR) of signals. The accuracy of the the method for the reconstructed signal is estimated. An example of application of the OMLR to the reconstruction of the temperature profile from the data obtained with a Raman lidar at the Siberian Lidar Station of the Institute of Atmospheric Optics (Tomsk, Russia) is given. The proposed method is distinguished by simplicity of interpretation of the criteria used, based on careful adherence to statistical principles. This method is shown to be an efficient auxiliary tool for the processing of measured data.

In this paper, we have investigated the main properties of the Raman and fluorescent matrix of scattering by microspheres using the matrix scattering formalism. The coherent and incoherent inelastic scattering of incident light by a microsphere is described by the Stokes parameters. We demonstrate the main symmetry properties of the coherent and incoherent Raman and fluorescent scattering matrices. Numerical results are presented to illustrate the Raman scattering efficiency, cross-phase coefficient, and some other parameters of scattering by microspheres.