216 research outputs found
Dependence of effective spectrum width of synchrotron radiation on particle energy
For an exact quantitative description of spectral properties in the theory of
synchrotron radiation, the concept of effective spectral width is introduced.
In the classical theory, numeric calculations of effective spectral width
(using an effective width not exceeding 100 harmonics) for polarization
components of synchrotron radiation are carried out. The dependence of the
effective spectral width and initial harmonic on the energy of a radiating
particle is established
Effective spectrum width of the synchrotron radiation
For an exact quantitative description of spectral properties of synchrotron
radiation (SR), the concept of effective width of the spectrum is introduced.
In the most interesting case, which corresponds to the ultrarelativistic limit
of SR, the effective width of the spectrum is calculated for the polarization
components, and new physically important quantitative information on the
structure of spectral distributions is obtained. For the first time, the
spectral distribution for the circular polarization component of the SR for the
upper half-space is obtained within classical theory
Liquid Film Coating a Fiber as a Model System for the Formation of Bound States in Active Dispersive-Dissipative Nonlinear Media
We analyze the coherent-structure interaction and the formation of bound states in active dispersivedissipative
nonlinear media using a viscous film coating a vertical fiber as a prototype. The coherent
structures in this case are droplike pulses that dominate the evolution of the film.We study experimentally
the interaction dynamics and show evidence for formation of bound states. A theoretical explanation is
provided through a coherent-structures theory of a simple model for the flow
Substantiating Ways of Load Application When Modeling Interaction of a Multiincisal Mining Machine Actuator With Rocks
Two methods of modeling of interaction between a mining machine working body and rocks are considered; a multi-cutter working body sum impact on rock stress-strain state in a cutter action zone is described; practicability of distributed forces application in math modeling is substantiated
The current status of orbital experiments for UHECR studies
Two types of orbital detectors of extreme energy cosmic rays are being
developed nowadays: (i) TUS and KLYPVE with reflecting optical systems
(mirrors) and (ii) JEM-EUSO with high-transmittance Fresnel lenses. They will
cover much larger areas than existing ground-based arrays and almost uniformly
monitor the celestial sphere. The TUS detector is the pioneering mission
developed in SINP MSU in cooperation with several Russian and foreign
institutions. It has relatively small field of view (+/-4.5 deg), which
corresponds to a ground area of 6.4x10^3 sq.km. The telescope consists of a
Fresnel-type mirror-concentrator (~2 sq.m) and a photo receiver (a matrix of
16x16 photomultiplier tubes). It is to be deployed on the Lomonosov satellite,
and is currently at the final stage of preflight tests. Recently, SINP MSU
began the KLYPVE project to be installed on board of the Russian segment of the
ISS. The optical system of this detector contains a larger primary mirror (10
sq.m), which allows decreasing the energy threshold. The total effective field
of view will be at least +/-14 degrees to exceed the annual exposure of the
existing ground-based experiments. Several configurations of the detector are
being currently considered. Finally, JEM-EUSO is a wide field of view (+/-30
deg) detector. The optics is composed of two curved double-sided Fresnel lenses
with 2.65 m external diameter, a precision diffractive middle lens and a pupil.
The ultraviolet photons are focused onto the focal surface, which consists of
nearly 5000 multi-anode photomultipliers. It is developed by a large
international collaboration. All three orbital detectors have multi-purpose
character due to continuous monitoring of various atmospheric phenomena. The
present status of development of the TUS and KLYPVE missions is reported, and a
brief comparison of the projects with JEM-EUSO is given.Comment: 18 pages; based on the rapporteur talk given by M.I. Panasyuk at
ECRS-2014; v2: a few minor language issues fixed thanks to the editor; to be
published in the proceeding
Pulse dynamics in low-Reynolds-number interfacial hydrodynamics: Experiments and theory
a b s t r a c t We analyze interaction of nonlinear pulses in active-dispersive-dissipative nonlinear media. A particular example of such media is a viscous thin film coating a vertical fibre. Experiments for this system reveal that the interface evolves into a train of droplike solitary pulses in which numerous inelastic coalescence events take place. In such events, larger pulses catch up with smaller ones and annihilate them. However, for certain flow conditions and after a certain distance from the inlet, no more coalescence is observed and the flow is described by quasi-equilibrium solitary pulses interacting continuously with each other through attractions and repulsions, and, eventually they form bound states of groups of pulses in which the pulses travel with the same velocities as a whole. This experimental study represents the first evidence of formation of bound states in low-Reynolds-number interfacial hydrodynamics. To gain theoretical insight into the interaction of the pulses and formation of bound states, we derive a weakly nonlinear model for the flow, the generalized Kuramoto-Sivashinsky (gKS) equation, that retains the fundamental mechanisms of the wave evolution, namely, dominant nonlinearity, instability, stability and dispersion. Much like in the experiments, the spatio-temporal evolution of the gKS equation is dominated by quasistationary solitary pulses which continuously interact with each other through coalescence events or attractions/repulsions. To understand the latter case, we utilize a weak-interaction theory for the solitary pulses of the gKS equation. The theory is based on representing the solution of the equation as a superposition of the pulses and an overlap function and leads to a coupled system of ordinary differential equations describing the evolution of the locations of the pulses, or, alternatively, the evolution of the separation distances. By analyzing the fixed points of this system, we obtain bound states of interacting pulses. For two pulses, we provide a criterion for the existence of a countable infinite or finite number of bound states, depending on the strength of the dispersive term in the equation. The interaction theory and resulting bound states are corroborated by computations of the full equation. We also find qualitative agreement between the theory and the experiments
The Radiating Unit Based on Hybrid Metal-Dielectric Structure with Bounded Sequence of Transverse Slots
Abstract The structure which consists of the five transverse slots based on inverted dielectric waveguide was experimentally investigated. The possibility of creat ing an antenna on the basis of the above mentioned waveguide with an acceptable radiation pattern and good agreement feed line and antenna are presented
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