Angular Characteristics Of Radiation Research Articles

Features of Edge Effect of Coherent Synchrotron Radiation of Relativistic Electrons

This paper considers the features of coherent synchrotron radiation generated when relativistic electron bunches pass the field of short magnets. A significant contribution to the spectral and angular characteristics of radiation can be made by a factor of the limited length of the magnetic field disposed along the trajectory of the electrons. Furthermore, a substantial contribution to these features can be made by a radiation coherence factor. This work comprises the theoretical analysis of these effects and the results of experimental studies in the millimeter wavelength range

The Debye’s Potentials Utilization in the Three-Dimensional Problems of the Radiation and Propagation of the Elastic Waves

Are studied internal and external tasks of radiat ion of a sound by the elastic bodies, excit ing by the harmonic point source, imitating turbulent pulsation of a flo w of a liquid. The angular characteristics of radiat ion of a hollow spheroidal shell are calcu lated. The characteristic equations of the axial three-d imensional flexural waves in the hollow cylindrical shell and cylindrical bar are received with the help of Debye's potentials. The phase velocities of the various forms of these waves for shells and for cylindrical bar are calculated.

Diffracted transition radiation of a relativistic electron in the artificial periodic multilayer medium

A theory of coherent X-ray radiation of a relativistic electron crossing the artificial periodic medium in the Laue scattering geometry is constructed. The expressions describing the spectral and angular characteristics of radiation in the direction of Bragg scattering are obtained and investigated. By analogy with the radiation emission in a crystalline medium this radiation is considered as the result of coherent summation of the contributions of two radiation mechanisms: parametric (PXR) and diffracted transition (DTR). It is shown that the yield of DTR from layered target can be more than one order higher than the yield in single crystal radiator, under similar conditions. The manifestations of the Borrmann effect for DTR in the artificial multilayer environment are demonstrated for a Laue scattering geometry.

Electromagnetic radiation at twice the plasma frequency emitted from the region of interaction of two short laser pulses in a rarefied plasma

We study the electromagnetic radiation at twice the plasma frequency, which emerges because of the interaction of two identical counterpropagating short laser pulses in a rarefied plasma and caused by excitation of small-scale standing plasma waves in the pulse overlap region. The energy, spectral, and angular characteristics of radiation are investigated, and the dependence of these characteristics on the parameters of the laser pulses is analyzed. The possibility of applying this effect for diagnostics of localized plasma oscillations is discussed.

Atmospheric Disturbances and Radiation Impulses Caused by Large-Meteoroid Impacts on the Surface of Mars. II. Radiation Impulse Characteristics and Parameters of the Warm Layer

This paper presents the results of the calculation of spectral and angular characteristics of radiation emitted by the disturbed region after the vertical impacts on the Martian surface of stony meteoroids with radii R0 from 1 to 100 m at speeds of 11–20 km/s. The time dependences are given for the density of the radiation flux incident on horizontal surface areas located at different distances from the impact point. For small impactors (R0= 1 m), the heating of the surface and surrounding gas by the radiation impulse from the hot region formed after the impact is insignificant even at the crater edge. However, the radiation impulse that heats up the surface is also emitted during the meteoroid flight through the atmosphere. Although this heating is insufficient to initiate evaporation, heat transfer by turbulent diffusion leads to the formation of a layer with temperatures that substantially exceed the initial temperature of the atmosphere. For large impactors (R0 = 100 m), the total specific impulse of the plume radiation gives rise to the emergence of the heated layer with a thickness on the order of several meters within several kilometers of the impact point. The formation of this “warm” layer may lead to the formation of a high-speed jet moving along the Martian surface as well as eddies at the front of the precursor with a subsequent intense rise of dust.

Accuracy in calculating the parameters of scattered radiation

The angular characteristics of radiation scattered by particles are calculated. The effect of the accuracy of the number representation during computations (number of decimal places) on the calculation results is analyzed. It is shown that, in order to obtain reliable results within the available algorithm, it is often necessary to use a precision that is much higher than computer precision. An algorithm is proposed and implemented that makes it possible to avoid going beyond computer precision in calculations in a considerably extended range of input parameters. A simple approximate formula is proposed to restrict the number of terms in infinite sums, which ensures the required accuracy in calculating the scattering indicatrix and the radiative properties of particles.

Spectral and angular characteristics of radiation produced by passage of 10 gev electrons through thick Si and Ge crystals

Abstract The results of studying the angular and spectral characteristics of X-rays produced by passage of 10 GeV electrons through sufficiently thick Si (0.8 and 3.0 mm) and Ge (0.5 mm) single crystals at small angles to the 〈111〉 crystallographic axis are presented. Information have been obtained on the excess of the spectralangular characteristics of radiation in the crystal over respective values for an amorphous target.

Influence of field rotation on the angular characteristics of radiation from a laser with an active medium containing random small-scale inhomogeneities

A numerical analysis is made of the influence of field rotation on the angular characteristics of radiation from a laser having an active medium containing random small-scale inhomogeneities.