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2017 year, number 3

1.
The self-broadening coefficients and spontaneus emission probability of the CO2 1000-0001 transition lines

K.I. Arshinov1, O.N. Krapivnaya1, V.V. Nevdakh2
1Institute of Technical Acoustics, Academy of Sciences of Belarus, Vitebsk, Belarus, Belarus, 210023, Vitebsk, prosp. Lyudnikova, 13
2Belarusian National Technical University, Belarus, 220013, Minsk, ul. Ya. Kolasa, 13
Keywords: углекислый газ, поглощение, коэффициент столкновительного самоуширения, вероятность спонтанного излучения, carbon dioxide, absorption, self-broadening coefficient, spontaneous emission probability

Abstract >>
Using a tunable frequency stabilized CO2 laser, the dependences of the unsaturated absorption coefficient in pure carbon dioxide on pressure were measured in the range 5-30 Torr, where line contours are described by the Voigt function. The absorption coefficients were measured at the center frequencies of R(8), R(22), R(34), P(22), and P(36) lines of the 1000-0001 transition in the temperature range 300-700 K. By means of the least squares method, the inverse problem is solved for the system of equations for absorption coefficients at different pressures in the temperature range under study. The self-broadening coefficient γCO2-CO2 and the probability of spontaneous emission Aik are determined. A new formula is proposed for the dependence γCO2-CO2(T).



2.
Kerr nonlinearity effect on femtosecond radiation pulse filamentation in air

N.G. Ivanov1, V.F. Losev1,2
1High Current Electronics Institute of the Siberian Branch of the RAS, 634055, Tomsk, 2/3, Academichesky ave.
2National Research Tomsk Polytechnic University, 30, Lenin Avenue, Tomsk, 634050, Russia
Keywords: керровская нелинейность, филаментация, фокусировка, суперконтинуум, Kerr nonlinearity, filamentation, focusing, supercontinuum

Abstract >>
The filamentation conditions of a femtosecond laser pulse by its focusing in air are investigated experimentally and theoretically. A good agreement is observed between experimental and calculated data when neglecting the filament plasma. It is shown that at low numerical aperture (NA ≤ 2.15 x 10-3), a Kerr nonlinearity plays a fundamental role in the formation, existence, and termination of a filament. At the initial stage, the Kerr effect leads to the beam self-focusing and emergence of the filament; at the final stage, to radiation defocusing and sharp decrease in its axial intensity due to the beam wave front distortions. In the case of aberration focusing, a spatial quasi-soliton is formed after a visible filament due to the balance between Kerr self-focusing and diffraction extending. The quasisoliton is a source of the directional white supercontinuum.



3.
Remote detector of hazardous substances based on a tunable 13С16О2 laser

B.G. Ageev, A.V. Klimkin, A.N. Kuryak, K.Yu. Osipov, Yu.N. Ponomarev
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: дистанционное детектирование, СО-лазер , опасные вещества, remote detection, СОlaser , hazardous substances

Abstract >>
Description of the developed prototype of a remote detector of hazardous substance vapors based on a tunable 13С16О2 laser is given. Results of test measurements of laser radiation transmission of organic liquid vapors (acetone, ammonia, ethanol, gasoline) are presented. The remote detection of acetone and ammonia vapors at distances up to 100 m is experimentally implemented.



4.
Lidar investigations of the resonance scattering of the atmosphere on exited ions of atomic nitrogen and oxygen

V.V. Bychkov1, I.N. Seredkin1, A.S. Perezhogin1, B.M. Shevtsov1, V.N. Marichev2
1Institute of Cosmophysical Research and Radio Wave Propagation of the Far-Eastern Branch of Russian Academy of Science, 684034 Kamchatka region, Elizovskiy district, Paratunka, Mirnaya str., 7
2V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
Keywords: атмосфера, ионосфера, лидар, рассеяние, зондирование, atmosphere, ionosphere, lidar, sounding, scattering

Abstract >>
The results of two-frequency lidar investigation at wavelengths of 561 and 532 nm of the atmosphere scattering are presented. The laser radiation band covers two emission lines of atomic oxygen and three emission lines of atomic nitrogen. The lines correspond to the transitions between the exited states of ions of atomic oxygen or nitrogen. The possibility of application of the lidar method for ionosphere investigations is discussed. The physical basis of this method may be the resonance scattering on upper atmosphere ions.



5.
Variations of carbon monoxide in the atmosphere during the atmospheric blocking event over European Russia in summer of 2010 (according to AIRS data)

S.A. Sitnov1, I.I. Mokhov1,2, A.V. Dzhola1
1A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences, Pyzhevsky per., 3, 119017, Moscow, Russia
2Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russia
Keywords: монооксид углерода, СО, атмосферное блокирование, природные пожары, европейская территория России, лето 2010 г, наземные спектрометрические измерения СО, carbon monoxide, atmospheric blocking, wildfires, European Russia, summer 2010, AIRS, ground-based spectrometer CO measurements

Abstract >>
The spatiotemporal variability of carbon monoxide (CO) during the atmospheric blocking event over European Russia in summer of 2010 is studied using the CO measurements from satellite Atmospheric Infrared Sounder (AIRS) instrument. Total column CO data from AIRS are compared with those from the ground-based spectrometer operated at Zvenigorod Scientific Station of A.M. Obukhov Institute of Atmospheric Physics. The peculiarities of CO field evolution conditioned by the regional atmospheric circulation associated with the omega block in the presence of severe wildfires are revealed.



6.
Mathematical modeling of convective cloudiness in polar regions

A.E. Aloyan1,2, V.O. Arutyunyan1, A.N. Ermakov3
1Institute of Numerical Mathematics of the Russian Academy of Sciences, Gubkin str., 8, Moscow, 119333, Russia
2Hydrometeorological Centre of Russia, 11-13, Bol'shoj Predtechenskij per., 123242, Moscow, Russia
3Institute of Energy Problems of Chemical Physics, Russian Academy of Sciences, Russia, 119334, Moscow, Leninskii prosp., 38, korp. 2
Keywords: численное моделирование, атмосфера, конвективная облачность, полярные мезомасштабные циклоны, конденсация, коагуляция, нуклеация, numerical simulation, atmosphere, convective cloudiness, polar mesoscale cyclones, condensation, coagulation, nucleation

Abstract >>
A three-dimensional numerical model of moist convection and formation of convective cloudiness in the Arctic atmosphere is considered. A model of mixed clouds with explicit description of liquid and ice phases is used with nonstationary equations for cloud-drop and ice-particle size distributions. The model capability in the reproduction of polar mesoscale cyclones in the Arctic atmosphere is analyzed.



7.
The analysis of variations in the saltating sand transfer velocity

A.V. Karpov, R.A. Gushchin, O.I. Datsenko
A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences, Pyzhevsky per., 3, 119017, Moscow, Russia
Keywords: динамика сальтации, прямые и обратные задачи, массовый поток сальтации, коэффициент скольжения, методика восстановления, saltation dynamics, direct and indirect problems, mass saltation flux, sliding coefficient, retrieving method

Abstract >>
A technique is developed for retrieving the vertical profile of the mass saltation flux from measurements of the saltating sand mass concentration and wind velocity in the surface air layer. The technique is based on the solution of direct and inverse problems of the saltation sand dynamics. In order to estimate the saltating sand sliding coefficient, calculation results are compared with measurements in wind channels. The conditions for the saltating sand trajectories to fall in the altitude ranges from 0.5 to 1.0 cm and from 1.0 to 2.0 cm are ascertained. The effects of the diameter, sand grain liftoff velocity and angle, and the friction velocity on the sliding coefficient are analyzed. The sliding coefficient for sand particles of 100 μm diameter is estimated for the first time.



8.
Resonance scattering of solar radiation by a freely expandind atomic cloud

N.I. Kosarev
Institute of Non-Ferrous Metals and Materials of the Siberian Federal University, 95, Prospect imeni gazety «Krasnojarskij rabochij», 660025, Russia
Keywords: перенос излучения, контур спектральной линии, доплеровская ширина, функция источников, коэффициент поглощения, radiation transport, contour of spectral line, Doppler width, source function, absorption coefficient

Abstract >>
Transfer of the solar radiation in a freely expanding spherical atomic cloud is numerically investigated. The spectral and spatial characteristics of the absorbed and scattered radiation are calculated; the influence of the expansion velocity of the medium on them are detected.



9.
The analysis of a correlation between climate change and thermocarst processes in the permafrost zone of Western Siberia

Y.M. Polishchuk1,2
1Institute of Monitoring of Climatic and Ecological Systems of the Siberian Branch of the Russian Academy of Sciences, 634055, Tomsk, 10/3, Academichesky ave
2National Research Tomsk Polytechnic University, 30, Lenin Avenue, Tomsk, 634050, Russia
Keywords: вечная мерзлота, космические снимки, термокарстовые озера, климатические изменения, Западная Сибирь, permafrost, space images, thermokarst lakes, climate change, Western Siberia

Abstract >>
The remote sensing results of the dynamics of thermokarst lake areas are presented. The study is carried out for 29 test sites in the permafrost zone of Western Siberia and covers 35 years. It shows a trend toward a decrease in the areas of thermokarst lakes during the period under study. The time series of climatic variables (temperature and precipitation), received from reanalysis, are analyzed. It is found that an increase in the annual average temperature is accompanied by a reduction in the areas of thermokarst lakes located in the permafrost zone of Western Siberia.



10.
Laboratory simulation of blue and red diffuse minijets in air environment

V.A. Panarin, V.S. Skakun, E.A. Sosnin, V.F. Tarasenko
High Current Electronics Institute of the Siberian Branch of the RAS, 634055, Tomsk, 2/3, Academichesky ave
Keywords: переходные световые явления, спрайты, стартеры, голубые струи, экспериментальное моделирование, апокамп, transient luminous events, sprites, starters, blue jets, experimental simulation, apokamp

Abstract >>
Air environment pulse-periodic discharge in apokamp mode is studied. It is confirmed that the blue and red diffuse minijets (apokamps) form from the plasma discharge channel under the floating potential. It is shown that at low pressures the apokamps are units-tens of centimeters in size and possess the properties inherent to giant plasma jets (sprites, starters, and blue jets) observed in the Earth's atmosphere at altitudes of 17-100 km. Morphological, spectral, and electrophysical parameters of apokamps in various conditions are ascertained. It is found that plasma minijets are easier implementable at the positive polarity of the discharge channel. A gradual change in the color of diffuse jets with a decrease in the air pressure is demonstrated.



11.
Europium vapor laser

V.O. Troitskii1, V.G. Sokovikov1, A.G. Filonov1, D.V. Shiyanov1,2
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 Polytechnic University, 30, Lenin Avenue, Tomsk, 634050, Russia
Keywords: лазеры на парах металлов, газоразрядный способ накачки, генерация на атоме европия, генерация на ионе европия, metal vapor lasers, gas discharge excitation, lasing on europium atom, lasing on europium ion

Abstract >>
The results of experimental study of a gas-discharge Ne-Eu laser are presented. In this work, lasing lines, pulse shapes in europium atom and ion in the conditions of this experiment are identified. Influence of the buffer gas pressure and pulse repetition rate on the energy characteristics of the laser is ascertained; their optimal values are determined. It is shown that under optimum operating conditions for the corresponding transitions the output power is 1 W at 1759 nm line and 70 mW at 664.5 nm line.



12.
Recovery of steady-state lasing in CuBr laser

N.A. Vasnev1,2, M.V. Trigub1,2, V.O. Troitskii1, V.A. Dimaki1, V.V. Vlasov1
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 Polytechnic University, 30, Lenin Avenue, Tomsk, 634050, Russia
Keywords: CuBr-лазер, цуговый режим, последовательность импульсов, лазерная генерация, накопительная емкость, CuBr laser, train of pulses, train mode, laser generation, storage capacity

Abstract >>
The recovery of steady-state lasing in a CuBr laser operating in the train mode is studied with the use of a computer-based control system. The control system provided the repetitively-pulsed, train, and waiting modes. The dependences of the recovery time on the pause duration and the strorage capacitor are derived. The specific recover times are determined; their dependences on the pause duration in the train mode are analyzed. A time delay between the start of pump pulses and appearance of lasing pulses is shown. The time where lasing is absent increases in the pause duration range from 0.2 to 10 ms; this time is set to about 15 ms if a pause is equal or longer than 10 ms.



13.
High-efficiency double-pulsed CuBr laser

A.I. Fedorov1, D.V. Shiyanov1,2
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 Polytechnic University, 30, Lenin Avenue, Tomsk, 634050, Russia
Keywords: СuBr-лазер, средняя мощность излучения, режим сдвоенных импульсов накачки, импульс диссоциации, удельная энергия, КПД лазера, СuBr laser, average output power, double-pulsed excitation, dissociation pulse, energy density, laser efficiency

Abstract >>
Results of research of the CuBr laser operating characteristics working in the double-pulse excitation mode with a pulse repetition rate of 50 Hz are given. The possibilities of increasing the efficiency by optimizing the parameters of the excitation pulse and matching with the impedance of the plasma formed by a dissociating pulse are considered. Laser efficiency of 2.56% at an excitation pulse with average power of 16 mW and time delay between dissociation and excitation pulses of 150 ms is received. Specific energy of the dissociating pulse reached 22 mJ/cm3; and of the exciting, 0.4 mJ/cm3. Introduction of saturation inductance into the excitation circuit provides for the maximum efficiency of 2.7%.