Inverse problem of reflection of electromagnetic waves from layered inhomogeneous plasma-like structures with refractive-index discontinuity

To reconstruct the distribution of free carriers in a layered inhomogeneous plasma-like half-space during the electromagnetic-wave reflection, we derive the Gelfrand-Levitan-Marchenko integral equation for structures with refractive-index discontinuity by the inverse problem method. Exact model solutions of the generalized equations are analyzed. The applicability limits and scope of these exact solutions for reconstruction problems are shown. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 1, pp. 31–39, January 2007     

Improving the efficiency of an acoustooptic modulator with a two-lobe directivity pattern by correcting the two-frequency electric signal

The feasibility of forming an efficient two-lobe directivity pattern at Bragg acoustooptic diffraction is theoretically substantiated for the first time. It is shown that the efficiency of diffraction into main beams can be increased by mixing the two-frequency signal with additional spectral components that correspond to the closest combination frequencies. Mixing is accomplished using an original electronic circuit designed for polynomial nonlinear correction of the control signal. Bragg diffraction by the corrected signal is studied experimentally in a high-efficiency paratellurite (TeO₂) modulator. Satisfactory agreement with the theory is obtained, and results of applied interest are obtained. In particular, the maximal overall efficiency of diffraction into two main beams is increased from 68 to 79%.     

Determination of the electron beam size at the Kurchatov synchrotron radiation source using an X-ray refractive lens

The electron beam size in the storage ring of the Kurchatov synchrotron radiation source at 2.5 GeV is determined using an x-ray two-dimensional parabolic refractive lens. The vertical size of the electron beam of the storage ring is found to be 270 μm, which exceeds the corresponding design value 140 μm (at a betatron coupling of 1%). The difference is explained by the imperfect geodetic arrangement of ring elements and the incomplete adjustment of the ring.     

Propagation of the forward front of an electromagnetic field in a dispersive medium

By solving the Cauchy problem with zero initial conditions for the Maxwell equations in a dispersive medium it is shown that the electromagnetic field produced by arbitrary external sources occupying a fixed volume at any point in time has a forward front which propagates with the velocity c just as in a vacuum.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 51–55, October, 1982.     

Capabilities of coupling dissimilar computer codes

A method for automatically controlling commercial computer codes is described. The coupling of the automation system of the EXAFS spectrometer controlled by a DOS-operated computer that we developed and the commercial program of a semiconductor-detector control installed on a Windows-operated computer is given as the example. The described complex system is used for the automation of the intermediate processing of amplitude spectra while measuring EXAFS spectra at the Kurchatov Synchrotron Radiation Source.