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41.
Cherenkov instability is considered in a completely magnetized homogeneous beam-plasma system featuring a thermal momentum spread of beam electrons. The thermal spread in the beam is described in the scope of both the hydrodynamic approach and the kinetic equation method by giving the electron momentum distribution function in the form of theMaxwellian and semi-Maxwellian distributions. It is shown that two beam-plasma instability regimes, the single-particle and collective Cherenkov effects (Compton and Raman regimes) differing by the physical mechanism and the increments, are possible in a system (waveguide) with homogeneous transverse beam and plasma density profiles. Solutions to dispersion equations for these and a more general regime are obtained and analyzed. 相似文献
42.
Naether U Kartashov YV Vysloukh VA Nolte S Tünnermann A Torner L Szameit A 《Optics letters》2012,37(4):593-595
We study the gradual transition from one-dimensional (1D) to two-dimensional (2D) Anderson localization upon transformation of the dimensionality of disordered waveguide arrays. An effective transition from a 1D to a 2D system is achieved by increasing the number of rows forming the arrays. We observe that, for a given disorder level, Anderson localization becomes weaker with increasing numbers of rows-hence the effective dimension. 相似文献
43.
We address Anderson localization of light in disordered optical lattices where the disorder strength varies across the transverse direction. Such variation changes the preferred domains where formation of localized eigenmodes is most probable, hence drastically impacting light localization properties. Thus, step-like disorder results in formation of modes with different decay rates at both sides of the interface, while a smoothly varying disorder yields appearance of modes that are extended within weakly disordered domains and rapidly fade away in strongly disordered domains. 相似文献
44.
We predict that a photonic crystal fiber whose strands are filled with a defocusing nonlinear medium can support stable bright solitons and also vortex solitons if the strength of the defocusing nonlinearity grows toward the periphery of the fiber. The domains of soliton existence depend on the transverse growth rate of the filling nonlinearity and nonlinearity of the core. Remarkably, solitons exist even when the core material is linear. 相似文献
45.
We consider the propagation of the laser beam near the interface between the linear dielectric and photorefractive medium with drift and diffusion nonlinearity. We demonstrated the possibility of the surface waves formation, found the profiles of such surface modes and investigated waveguiding properties of the dielectric-photorefractive medium boundary. The effective particle theory was used to derive an ordinary differential equation that describes the beam center trajectory during the reflection from the interface. 相似文献
46.
V.G. Alpatov Yu.D. Bayukov A.V. Davydov Yu.N. Isaev G.R. Kartashov M.M. Korotkov V.E. Rad'ko A.A. Sadovsky V.M. Samoylov 《Hyperfine Interactions》1997,107(1-4):231-246
The temperature dependence of the 109Ag γ-ray self-absorption was investigated for the horizontal and vertical directions of emission. The source was a single-crystal
silver plate containing atoms of parent radionuclide 109Cd. Gamma-radiation of this γ-source and that of the monitoring γ-source, 57Co, were registered by a pair of Ge(Li)-detectors. As a result of cooling the source from 77 K to ~12 K a relative decrease
was observed of the intensity of the horizontally emitted γ-rays equal to 0.00064±0.00044. For the vertical direction the
corresponding intensity change turned out to be -0.00047±0.00051. Although these data, as one would see, give some evidence
for the possible effect of the gravitation on the resonant γ-ray absorption, future measurements must show if these results
aren’t a consequence of any apparatus effect. The ways for developments in this study are discussed and some hindrances are
considered.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
47.
V. R. Kartashov T. N. Sokolova A. B. Radbil E. V. Skorobogatova 《Russian Chemical Bulletin》1995,44(2):336-344
The kinetics of the addition of Hg(OAc)2 to strained and unstrained alkenes was studied in MeOH solution in the presence of NaOAc. Based on salt effects, the HgOAc ion was shown to be the actual reagent in the reaction of the unstrained alkenes, whereas Hg(OAc)2 was the reagent in the case of the strained alkenes. The mechanisms of the solvomercuration of alkenes of various structures were proposed.For the previous report seeIzv. Akad. Nauk, Ser. Khim., 1994, 819 [Russ. Chem. Bull., 1994,43, 760 (Engl. Transl.)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 344–352, February, 1995. 相似文献
48.
E. V. Skorobogatova E. P. Traktina I. I. Grinvald A. P. Arbatskii V. R. Kartashov 《Russian Journal of Applied Chemistry》2008,81(4):708-713
Fundamental aspects of the complexation of cobalt(II) and nickel(II) ions with chitosan hydrochloride in water and chitosan in an aqueous solution of acetic acid were studied. The relation between the numbers of chitosan moles and metal ions involved in the interaction was found. The optimal conditions for synthesis of complexes were determined and their chemical composition and spectral properties were analyzed. The possible reaction mechanisms were discussed. 相似文献
49.
We report on the existence of nonlinear surface waves that, on the one hand, do not require the threshold energy flow for their excitation, and, on the other hand, extend into media at both sides of the interface at low powers, i.e., cannot be reduced to the conventional Tamm states. Such waves can be excited if the refractive index in at least one of the materials forming the interface is periodically modulated, with properly selected modulation depth and frequency. Thresholdless surface solitons can be stable in the entire existence domain. 相似文献
50.
We reveal that lattice interfaces imprinted in nonlocal nonlinear media support surface solitons that do not exist in other similar settings, including interfaces of local and nonlocal uniform materials. We show the impact of nonlocality on the domains of existence and stability of the surface solitons, focusing on new types of dipole solitons residing partially inside the optical lattice. We find that such solitons feature strongly asymmetric shapes and that they are stable in large parts of their existence domain. 相似文献