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Найдено документов в текущей БД: 9

    Peculiarities of Alfven wave propagation along a nonuniform magnetic flux tube
[Text] / N. V. Erkaev [et al.] // Phys. Plasmas. - 2005. - Vol. 12, Is. 1. - Ст. 12905, DOI 10.1063/1.1833392. - Cited References: 18 . - ISSN 1070-664X
РУБ Physics, Fluids & Plasmas

Аннотация: Within the framework of the assumption of large azimuthal wave numbers, the equations for Alfven and slow magnetosonic waves are obtained using frozen-in material coordinates. These equations are specified for the case of a nonuniform magnetic field with axial symmetry. Assuming a meridional polarization of the magnetic field and velocity perturbations, the effects of Alfven wave propagation are analyzed which are related to geometric characteristics of a nonuniform magnetic field: (a) A finite curvature radius of the magnetic field lines and (b) convergence of magnetic field lines. The interaction between the Alfven and magnetosonic waves is found to be strongly dependent on the curvature radius of the magnetic tube and the local plasma beta parameter. The electric field amplitude and the length scale of a wave front are found to increase very strongly in the course of the Alfven wave propagation along a converging magnetic flux tube. Also studied is a temporal decrease of the wave perturbations which is caused by dissipation at the conducting boundary. (C) 2005 American Institute of Physics.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Shaidurov, V.A.; Semenov, V.S.; Langmayr, D.; Biernat, H.K.

    Loss of hydrogen and oxygen from the upper atmosphere of Venus
[Text] / H. Lammer [et al.] // Planet Space Sci. - 2006. - Vol. 54, Is. 13-14. - P1445-1456, DOI 10.1016/j.pss.2006.04.022. - Cited References: 93 . - ISSN 0032-0633
РУБ Astronomy & Astrophysics

Аннотация: Atmospheric escape from the upper atmosphere of Venus is mainly influenced by the loss of hydrogen and oxygen caused by the interaction of solar radiation and particle flux with the unprotected planetary environment. Because one main aim of the ASPERA-4 particle/plasma and VEX-MAG magnetic field experiments on board of ESA's forthcoming Venus Express mission is the investigation of atmospheric erosion processes from the planet's ionosphere-exosphere environment, we study the total loss of hydrogen and oxygen and identified the efficiency of several escape mechanisms involved. For the estimation of pick up loss rates we use a gas dynamic test particle model and obtained average loss rates for H+, and O+ pick up ions of about 1 x 10(25) s(-1) and about 1.6 x 10(25) s(-1), respectively. Further, we estimate ion loss rates due to detached plasma clouds, which were observed by the pioneer Venus orbiter and may be triggered by the Kelvin-Helmholtz instability of about 0.5-1 x 10(25) s(-1). Thermal atmospheric escape processes and atmospheric loss by photo-chemically produced oxygen atoms yield negligible loss rates. Sputtering by incident pick up O+ ions give O atom loss rates in the order of about 6 x 10(24) s(-1). On the other hand, photo-chemically produced hot hydrogen atoms are a very efficient loss mechanism for hydrogen on Venus with a global average total loss rate of about 3.8 x 10(25) s(-1), which is in agreement with Donahue and Hartle [1992. Solar cycle variations in H+ and D+ densities in the Venus ionosphere: implications for escape. Geophys. Res. Lett. 12, 2449-2452] and of the same order but less than the estimated H+ ion outflow on the Venus nightside of about 7.0 x 10(25) s(-1) due to acceleration by an outward electric polarization force related to ionospheric holes by Hartle and Grebowsky [1993. Light ion flow in the nightside ionosphere of Venus. J. Geophys. Res. 98, 7437-7445]. Our study indicates that on Venus, due to its larger mass and size compared to Mars, the most relevant atmospheric escape processes of oxygen involve ions and are caused by the interaction with the solar wind. The obtained results indicate that the ratio between H/O escape to space from the Venusian upper atmosphere is about 4, and is in a much better agreement with the stoichiometrically H/O escape ratio of 2:1, which is not the case on Mars. However, a detailed analysis of the outflow of ions from the Venus upper atmosphere by the ASPERA-4 and VEX-MAG instruments aboard Venus Express will lead to more accurate atmospheric loss estimations and a better understanding of the planet's water inventory. (c) 2006 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Lammer, H.; Lichtenegger, H.I.M.; Biernat, H.K.; Erkaev, N.V.; Еркаев, Николай Васильевич; Arshukova, I.L.; Kolb, C.; Gunell, H.; Lukyanov, A.; Holmstrom, M.; Barabash, S.; Zhang, T.L.; Baumjohann, W.

    Dissipation of Alfven wave pulses propagating along dipole magnetic tubes with reflections at the ionosphere
[Text] / N. V. Erkaev [et al.] ; ed. H. K. Biernat // BOUNDARY LAYERS, WAVES AND NON-LINEAR DYNAMICAL PROCESSES. Ser. ADVANCES IN SPACE RESEARCH : ELSEVIER SCIENCE LTD, 2006. - Vol. 37: 35th COSPAR Scientific Assembly (JUL 18-25, 2004, Paris, FRANCE), Is. 3. - P576-580, DOI 10.1016/j.asr.2005.09.002. - Cited References: 7 . - ISBN 0273-1177
РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: A ratio of the maximal and minimal cross sections of the magnetic tube (contraction ratio) is a crucial parameter which affects very strongly on reflections of MHD wave pulses propagating along a narrowing magnetic flux tube. In cases of large contraction ratios of magnetospheric magnetic tubes, the wave energy flux at the ionospheric boundary can be rather small. Therefore the dissipation of the wave perturbations can be very weak for each reflection, in spite of a finite conductivity of the planet's ionosphere. The dissipation is stronger for the pulses with shorter wave scales. Because of that, Alfven wave pulses with sufficiently long wave scales have a very small energy loss for each reflection at the conducting ionosphere, and thus, they have many reflections without a noticeable decrease of their amplitude. This effect related to converging magnetic lines is dependent very strongly on the polarization of the Alfven wave. In case of a dipole magnetic field, the effect is most pronounced for wave pulses characterized by velocity and magnetic perturbations in the meridional plane. (C) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Shaidurov, V.A.; Semenov, V.S.; Biernat, H.K.; Heidorn, D.; Biernat, H.K. \ed.\

    Theoretical description of spin-selective reactions of radical pairs diffusing in spherical 2D and 3D microreactors
/ K. L. Ivanov, V. M. Sadovsky, N. N. Lukzen // J Chem Phys. - 2015. - Vol. 143, Is. 8, DOI 10.1063/1.4928648 . - ISSN 0021-9606
Аннотация: In this work, we treat spin-selective recombination of a geminate radical pair (RP) in a spherical "microreactor," i.e., of a RP confined in a micelle, vesicle, or liposome. We consider the microreactor model proposed earlier, in which one of the radicals is located at the center of the micelle and the other one undergoes three-dimensional diffusion inside the micelle. In addition, we suggest a two-dimensional model, in which one of the radicals is located at the "pole" of the sphere, while the other one diffuses on the spherical surface. For this model, we have obtained a general analytical expression for the RP recombination yield in terms of the free Green function of two-dimensional diffusion motion. In turn, this Green function is expressed via the Legendre functions and thus takes account of diffusion over a restricted spherical surface and its curvature. The obtained expression allows one to calculate the RP recombination efficiency at an arbitrary magnetic field strength. We performed a comparison of the two models taking the same geometric parameters (i.e., the microreactor radius and the closest approach distance of the radicals), chemical reactivity, magnetic interactions in the RP and diffusion coefficient. Significant difference between the predictions of the two models is found, which is thus originating solely from the dimensionality effect: for different dimensionality of space, the statistics of diffusional contacts of radicals becomes different altering the reaction yield. We have calculated the magnetic field dependence of the RP reaction yield and chemically induced dynamic nuclear polarization of the reaction products at different sizes of the microreactor, exchange interaction, and spin relaxation rates. Interestingly, due to the intricate interplay of diffusional contacts of reactants and spin dynamics, the dependence of the reaction yield on the microreactor radius is non-monotonous. Our results are of importance for (i) interpreting experimental data for magnetic field effects on RP recombination in confined space and (ii) for describing kinetics of chemical reactions, which occur predominantly on the surfaces of biomembranes, i.e., lipid peroxidation reactions. © 2015 AIP Publishing LLC.

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Держатели документа:
International Tomography Center, Siberian Branch, Russian Academy of Sciences, Institutskaya St. 3a, Novosibirsk, Russian Federation
Novosibirsk State University, Pirogova St. 2, Novosibirsk, Russian Federation
Institute of Computational Modeling, Siberian Branch, Russian Academy of Sciences, Akademgorodok 50/44, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Sadovsky, V.M.; Садовский, Владимир Михайлович; Lukzen, N. N.

    Возможности построения радиосвязи с помощью орбитальных отражателей и магнитных антенн вращающейся поляризации
[Текст] : статья / Н. А. Тестоедов [и др.] // Вестник Сибирского государственного аэрокосмического университета им. академика М.Ф. Решетнева. - 2015. - Т. 16, № 2. - С. 364-367 . - ISSN 1816-9724
   Перевод заглавия: The possibility of constructing a radio communication using orbital reflectors and magnetic antennas polarization rotating

Кл.слова (ненормированные):
radio -- microsatellites -- magnetic antennas -- радиосвязь -- микроспутники -- магнитные антенны

Аннотация: Применение космоса для традиционных радиолюбительских приложений возможно с помощью относительно дешевых маложивущих микроспутников, которые выводятся на низкие орбиты экипажем космической станции. Радиосвязь может быть построена на базе отражателей и частотно-независимых малых магнитных антенн с вращающейся поляризацией, которые должны выполнять специальную функцию - связывать излученную в пространстве электромагнитную энергию с электронными компонентами аппаратуры, и поэтому они являются одними из основных элементов, определяющих построение радиотехнических систем. Поскольку в природе нет магнитных зарядов и, следовательно, нет магнитного тока, понимаемого как движение этих зарядов, то магнитный излучатель как элемент магнитного тока не может быть осуществлен, однако если антенный излучатель изначально создает переменное вращающееся вихревое магнитное поле, создать антенну возможно, реализовав в ней свойства магнитоэлектрической индукции. Первая телефонная спутниковая связь между Америкой и Великобританией была налажена через массивный экспериментальный американский спутник Echo1, запущенный на низкую околоземную орбиту, который представлял собой шар диаметром около 30 м, изготовленный из радиоотражающего материала. Тип такого спутника связи можно применить и в предлагаемой радиосвязи. Однако поскольку приемные и передающие антенны являются узконаправленными, то космический аппарат должен иметь на орбите такую ориентацию, чтобы он принял сигнал и отразил его. Диаметр сферы при этом может быть значительно меньших размеров, а положение на орбите можно удерживать корректирующей двигательной установкой, расположенной в центре масс. Радиоотражающая поверхность может быть выполнена из надувной пленки или сетеполотна, изготовленного, например, из позолоченной вольфрамовой проволоки диаметром порядка 30 мкм, разворачиваемого в сферу в трансформируемой конструкции. Возможен вариант выполнения сетеполотна из магнитно-мягкого материала типа сталей Э8, Э10, железа «Армко» или пермаллоя, которые являются идеальными проводниками магнитных потоков и не требуют охлаждения до криогенных температур.
The use of space for traditional Amateur radio applications is possible using relatively cheap only briefly long microsatellites, which are displayed on a low orbit of the space station crew. The radio can be built on the basis of reflectors and frequency-independent small magnetic antenna with circular polarization, which must fulfill a special function: to associate radiated into space electromagnetic energy with electronic components of the apparatus, and therefore are one of the main defining elements of the building radio systems. Since there are no magnetic charges, and therefore, no magnetic current, understood as the movement of these charges, a magnetic emitter, a magnetic current element, cannot be accomplished, however, if the antenna radiator initially creates an alternating rotating vortex magnetic field, it is possible to create the antenna having in it the properties of magneto-electric induction. The first satellite phone communication between America and Britain was established through a massive experimental American satellite Echo1, launched into low earth orbit, which represented a ball with a diameter of about 30 m, made of radiotracer material. The type of such a communication satellite can be used in the proposed radio communications. However, since the receiving and transmitting antennas are highly directional, the spacecraft must be in the orbit of such an orientation that it took the signal and reflected it. The diameter of the sphere can be much smaller, and the position in orbit to keep a corrective propulsion system, located in the center of mass. Radioreflective surface may be made of an inflatable film or setpolicy made, for example, of gold-plated tungsten wire with a diameter of about 30 ?m deployed in the field in transformable structures. Possible embodiment of setpolicy of magnetically soft material type steel A, E, iron “Armco” or permalloy, which are perfect conductors of magnetic flux and do not require cooling to cryogenic temperatures.

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Держатели документа:
АО «Информационные спутниковые системы» имени академика М. Ф. Решетнёва»
Институт вычислительного моделирования СО РАН

Доп.точки доступа:
Тестоедов, Н.А.; Testoedov N.A.; Двирный, В.В.; Dvirnyi V.V.; Крушенко, Генрих Гаврилович; Krushenko G.G.; Двирный, Г.В.; Dvirnyi G.V.

    Thermal limiting effects in optical plasmonic waveguides
/ A. E. Ershov [et al.] // J. Quant. Spectrosc. Radiat. Transf. - 2017. - Vol. 191. - P1-6, DOI 10.1016/j.jqsrt.2017.01.023 . - ISSN 0022-4073
Аннотация: We have studied thermal effects occurring during excitation of optical plasmonic waveguide (OPW) in the form of linear chain of spherical Ag nanoparticles by pulsed laser radiation. It was shown that heating and subsequent melting of the first irradiated particle in a chain can significantly deteriorate the transmission efficiency of OPW that is the crucial and limiting factor and continuous operation of OPW requires cooling devices. This effect is caused by suppression of particle's surface plasmon resonance due to reaching the melting point temperature. We have determined optimal excitation parameters which do not significantly affect the transmission efficiency of OPW. © 2017

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Держатели документа:
Institute of Computational Modeling, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Institute of Nanotechnology, Spectroscopy and Quantum Chemistry, Siberian Federal University, Krasnoyarsk, Russian Federation
Siberian State Aerospace University, Krasnoyarsk, Russian Federation
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Royal Institute of Technology, Stockholm, Sweden
The Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States

Доп.точки доступа:
Ershov, A.E.; Ершов, Александр Евгеньевич; Gerasimov, V. S.; Gavrilyuk, A.P.; Гаврилюк, Анатолий Петрович; Karpov, S. V.; Zakomirnyi, V. I.; Rasskazov, I. L.; Polyutov, S. P.

    Titanium nitride nanoparticles as an alternative platform for plasmonic waveguides in the visible and telecommunication wavelength ranges
/ V. I. Zakomirnyi [et al.] // Photonics Nanostruc. Fundam. Appl. - 2018. - Vol. 30. - P50-56, DOI 10.1016/j.photonics.2018.04.005 . - ISSN 1569-4410
Аннотация: We propose to utilize titanium nitride (TiN) as an alternative material for linear periodic chains (LPCs) of nanoparticles (NPs) which support surface plasmon polariton (SPP) propagation. Dispersion and transmission properties of LPCs have been examined within the framework of the dipole approximation for NPs with various shapes: spheres, prolate and oblate spheroids. It is shown that LPCs of TiN NPs support high-Q eigenmodes for an SPP attenuation that is comparable with LPCs from conventional plasmonic materials such as Au or Ag, with the advantage that the refractory properties and cheap fabrication of TiN nanostructures are more preferable in practical implementations compared to Au and Ag. We show that the SPP decay in TiN LPCs remains almost the same even at extremely high temperatures which is impossible to reach with conventional plasmonic materials. Finally, we show that the bandwidth of TiN LPCs from non-spherical particles can be tuned from the visible to the telecommunication wavelength range by switching the SPP polarization, which is an attractive feature for integrating these structures into modern photonic devices. © 2018 Elsevier B.V.

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Держатели документа:
Institute of Nanotechnology, Spectroscopy and Quantum Chemistry, Siberian Federal University, Krasnoyarsk, Russian Federation
School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, Sweden
The Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
Institute of Computational Modeling, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Siberian State University of Science and Technology, Krasnoyarsk, Russian Federation
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Zakomirnyi, V. I.; Rasskazov, I. L.; Gerasimov, V. S.; Ershov, A. E.; Polyutov, S. P.; Karpov, S. V.; Agren, H.

    Brownian dynamics of the self-assembly of complex nanostructures in the field of quasi-resonant laser radiation
/ V. S. Kornienko [et al.] // Photonics Nanostruc. Fundam. Appl. - 2019. - Vol. 35. - Ст. 100707, DOI 10.1016/j.photonics.2019.100707 . - ISSN 1569-4410
Аннотация: Self-assembly of nanoparticles under the action of laser field can be an universal method for the formation of nanostructures with specific properties for application in sensorics and nanophotonics. For prognosis of the self-assembly processes, the model of movement of an ensemble of nanoparticles in a viscous media under the action of laser radiation with the account for interaction of laser-induced polarizations and Brownian dynamics is developed. This model is applied to the investigation of the self-assembly process of a triple of nanoparticles into three-particle structure with a predetermined geometry.Two specific cases of formation of nanostructure from a preliminarily formed pair of particles are studied: either for the pair fixed in space or from the unfixed pair of nanoparticles. The geometry of resulting nanostructures is shown to be determined by the polarization direction of laser radiation and the laser wavelength. Under proper choice of these parameters the formation of structures is shown to be highly efficient. E. g., maximum probability of structures formation is as hig as 36–46% per single laser pulse of 10 ns duration. © 2019 Elsevier B.V.

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Держатели документа:
Siberian Federal University, Krasnoyarsk, Russian Federation
Department of Computational Mathematics, Institute of Computational Modeling of Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Laboratory of Coherent Optics, Kirensky Institute of Physics Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Kornienko, V. S.; Tsipotan, A. S.; Aleksandrovsky, A. S.; Slabko, V. V.

    Processes underlying the laser photochromic effect in colloidal plasmonic nanoparticle aggregates*
/ A. E. Ershov, V. S. Gerasimov, I. L. Isaev [et al.] // Chin. Phys. B. - 2020. - Vol. 29, Is. 3. - Ст. 037802, DOI 10.1088/1674-1056/ab6551. - Cited References:38. - Project funded by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science (Grant 18-42-243023), the RF Ministry of Science and Higher Education, and the State Contract with Siberian Federal University for Scientific Research. A.E. thanks the grant of the President of Russian Federation (agreement 075-15-2019-676). . - ISSN 1674-1056. - ISSN 1741-4199
РУБ Physics, Multidisciplinary

Аннотация: We have studied the dynamic and static processes occurring in disordered multiparticle colloidal Ag aggregates with natural structure and affecting their plasmonic absorption spectra under pico- and nanosecond pulsed laser radiations, as well as the physical origin responsible for these processes. We have shown that depending on the duration of the laser pulse, the mechanisms of laser modification of such aggregates can be associated both with changes in the resonant properties of the particles due to their heating and melting (picosecond irradiation mode) and with the particle shifts in the resonant domains of the aggregates (nanosecond pulses) which depend on the wavelength, intensity, and polarization of the radiation. These mechanisms result in formation of a narrow dip in the plasmonic absorption spectrum of the aggregates near the laser radiation wavelength and affect the shape and position of the dip. The effect of polydispersity of nanoparticle aggregates on laser photochromic reaction has been studied.

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Держатели документа:
RAS, SB, Inst Computat Modeling, Krasnoyarsk 660036, Russia.
Siberian Fed Univ, Krasnoyarsk 660041, Russia.
RAS, SB, KSC, Kirensky Inst Phys,Fed Res Ctr, Krasnoyarsk 660036, Russia.
Siberian State Univ Sci & Technol, Krasnoyarsk 660014, Russia.

Доп.точки доступа:
Ershov, A. E.; Gerasimov, V. S.; Isaev, I. L.; Gavrilyuk, A. P.; Karpov, S., V; Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR); Government of the Krasnoyarsk Territory [18-42-243023]; Krasnoyarsk Regional Fund of Science [18-42-243023]; RF Ministry of Science and Higher Education; Siberian Federal University for Scientific Research; Russian FederationRussian Federation [075-15-2019-676]