Radiation of charged plasma in magnetic field
Radiation of charged plasma in magnetic field
N.D.Naumov
An expression is obtained for the radiant intensity of a collisionfree cold plasma. This radiation is attributed to the action of external and collective fields. The radiant intensity of a stationary relativistic electronic beam propagating parallel to a uniform magnetic field is found.
Show AbstractК$_{π^{0}}$-distribution in the interactions of nucleons at energy ~ 5 TeV with carbon nuclei
К$_{π^{0}}$-distribution in the interactions of nucleons at energy ~ 5 TeV with carbon nuclei
V.Ya. Shestоpeгоv
The К$_{π^{0}}$ distribution in interactions between nucleons with mean energies of about 5 TeV and nuclei of atomic carbon is obtained by means of controlled nuclear photoemulsions. The result is compared to highenergy accelerator data.
Show AbstractОбратная задача скалярной дифракции
Обратная задача скалярной дифракции
В.А. Буров, А.А. Горюнов
Предложен метод постановки и решения обратных краевых скалярных задач дифракции. Подробно рассмотрена задача, обратная первой краевой (обратная задача Дирихле). При этом предполагалось, что рассеянное поле замеряется на ограниченной области, расположенной в ближней зоне рассеивателя, а источники первичного (падающего) поля заданы априори. Неизвестное значение нормальной производной рассеянного поля на поверхности рассеивателя определялось на основании замеров, рассеянного поля на приемной апертуре. Методом максимального правдоподобия получен нелинейный алгоритм обработки рассеянного поля, дающий оптимальную оценку формы граничного рассеивателя в предположении наличия помех двух типов. Показано, что в линейном приближении совместно с приближениями дальней:зоны предлагаемый алгоритм переходит в известный.
Show AbstractPhotoproduction of neutrinos on electrons in the two-dimensional qed approximation
Photoproduction of neutrinos on electrons in the two-dimensional qed approximation
Yu.М. Loskutov, V.V. Skobelev
Typical reactions of electronic- and muonic - neutrino production on the electron in a strong magnetic field are discussed in a Weinberg model. The resulting ratio of the corresponding cross sections, which depends on the mass of the charged boson, is, in principle, encouraging as to the possibility of estimating its mass from neutron - star neutrinoluminosity experiments.
Show AbstractBalance equation for nonequilibrium electrons distribution in the mobility gap of disordered semiconductor in presence of light
Balance equation for nonequilibrium electrons distribution in the mobility gap of disordered semiconductor in presence of light
V.B. Sulimоv
A balance equation is derived for determination of the average occupation number of a certain state in the forbidden band when a disordered semiconductor is illuminated by monochromatic light. The method of none quilibrium temporal Green's functions is used for the calculation. Expressions are found for the nonequilibrium single-particle functions. Perturbation theory is used to take the effects of the light into account. The conditions to be imposed on the parameters of the problem for validity of the balance equation are stated. Among other things, it is shown that the mass - operator component that fluctuates with the period of the light can be neglected if the electron - phonon interaction constant is sufficiently small.
Show AbstractOn the Green's functions of classical dynamical systems
On the Green's functions of classical dynamical systems
N.V. Peskov
An algorithm for approximate calculation of the Green's function for nonlinear infinite - dimensional dynamic systems on the basis of series expansion of the canonical transformation that converts the nonlinear system to a linear one is described. A nonlinear wave equation with a cubic term is considered as an example.
Show AbstractA continuous laser with a lightguide resonator
A continuous laser with a lightguide resonator
A.M. Zabelin, S.K. Isaev, L.S. Kornienko, V.V. Firsov
The development and testing of a continuous garnet laser with a length of multimode quartz lightguide in its resonator is reported. Optimum conditions for excitation of various transverse modes in a laser with a lightguide resonator are calculated. It is established that strong transverse - index mode selection occurs in the lightguide resonator. It is shown experimentally that small changes in the configuration of the resonator can be made to tune the laser from one transverse mode to another. A single-mode regime corresponding to the selected lightguide mode is then excited in the multimode fiber. The calculated and experimental results indicate that incorporation of a lightguide into a laser resonator is an effective way to excite a single lightguide mode in a multimode fiber.
Show AbstractThe fast Fourier transformation in the problem of thermal self-action
The fast Fourier transformation in the problem of thermal self-action
S.S. Chesnokov
The use of a spectral method based on the fast Fourier transformation to investigate the thermal defocusing of light beams in moving media Is described. The effectiveness of the approach in problems of the diffraction and self-action of beams with complex initial intensity distributions is discussed. An example is considered.
Show AbstractCoherent properties of X-Ray sources and coherence effects in X-Ray optics. I. Spatial coherence of synchrotrone radiation
Coherent properties of X-Ray sources and coherence effects in X-Ray optics. I. Spatial coherence of synchrotrone radiation
S.A. Akhmanov, B.A. Grishanin, G.A. Lyakhov, Yu.V. Ponomarуоv
The correlation properties of syncrotron radiation are analyzed in the classical approximation with allowance for the random radial structure of the electron bunch and its relativistic and extended nature. It Is. shown that the classical treatment has limited validity for description of the coherence of hard X-radiation from a synchrotron source. The energy parameters of dynamic scattering (DS) of partially coherent Xray beams In perfect crystals are calculated. The effects of Imperfect coherence on extinction beats and the anomalous passage of waves under DS conditions are analyzed. The increase in the radius of coherent radiation due to the interference nature of DS is calculated. A method for measuring the coherence radius in the X-ray band with use of DS effects is discussed.
Show AbstractCoherent properties of X-Ray sources and coherence effects in X-Ray optics. II. Dynamical scattering of partially coherent X-Ray emission by crystals
Coherent properties of X-Ray sources and coherence effects in X-Ray optics. II. Dynamical scattering of partially coherent X-Ray emission by crystals
S.A. Akhmanov, B.A. Crishanin, G.A. Lyakhov, Yu.V. Роnomаrуоv
The theory of dynamic scattering in perfect crystals is generalized to the scattering of partially coherent X - radiation. It is shown that, both the temporal and spatial incoherences have a strong influence on the course of the p rincipal effects: extinction beats are moved and anomalous transmission (the Borrman effect) deteriorates. The method of slow amplitudes is used to obtain general results that describe the transformation of the correlation functions of a scattered X-ray beam. It is shown that the coherence radius increases on dynamic scattering (in the X-ray analog of the van Zittert-Zernicke theorem). It is found that the extinction-beat smoothing effect can be used as a basis for measurement of the correlation functions; opportunities for obtaining information on the spatial and temporal correlation functions separately are examined.
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