Thickness of the damaged layer along the track made by a high-energy ion in polyimide

The thickness of the damaged layer along a particle track in polyimide is estimated by the method of thermally stimulated exoelectron emission and found to be ∼30 nm. Pis’ma Zh. Tekh. Fiz. 23, 68–71 (December 12, 1997)     

Evolution of the morphological structure of a two-dimensional cluster obtained with a linear microparticle trajectory in the diffusion-limited aggregation regime

Two-dimensional diffusion-limited aggregation of spherical microparticles was achieved experimentally as a result of their rectilinear motion (“ballistic aggregation”) at a “water-air” interface. A percolation cluster was obtained and the evolution of its morphological parameters was studied under compression. A change in the orientation of the cluster pores and a nonlinear coalescence and breakup process were observed. A fabrication technology is proposed for monolayer films similar to the Langmuir method. Pis’ma Zh. Tekh. Fiz. 25, 80–85 (December 12, 1999)     

Reconstruction of the X-ray emission spectrum of a nanosecond creeping discharge

A method is proposed for determining the soft x-ray emission spectrum of a nanosecond creeping discharge. The method includes a determination of the photoelectron density from photocurrent measurements and a calculation of the spectral flux density. The results are compared with experimental data on the wavelength interval of maximum radiation intensity. Pis’ma Zh. Tekh. Fiz. 24, 39–44 (April 12, 1998)     

Possibility of quasicontinuous measurement of the evolution of the electron temperature of a plasma by the Thomson scattering method

A method is proposed for increasing the frequency of Thomson scattering measurements of the electron temperature of a plasma to 100 kHz. The approach makes it possible to raise the diagnostic sensitivity under stationary discharge conditions by three orders of magnitude. The possibilities of the method are confirmed experimentally. Pis’ma Zh. Tekh. Fiz. 23, 34–40 (September 12, 1997)     

Induction self-acceleration of a high-current electron beam

Computer modeling using the particle-in-cell method confirmed that self-acceleration by induction of a high-current relativistic electron beam predicted by G. A. Askar’yan [At. énerg. 6, 658 (1959)] may occur when this beam passes through a thick diaphragm containing an aperture. Pis’ma Zh. Tekh. Fiz. 25, 52–56 (July 26, 1999)     

Identification of self-organizing structures by the numerical simulation of laminar three-dimensional flow around a crater on a plane by a flow of viscous incompressible fluid

Three-dimensional steady-state vortex structures which undergo self-organization during flow around a deep spherical crater on a plane are analyzed by using a factorized finite-volume method to solve the Navier-Stokes equations in a simplified approach based on an analytic definition of metric coefficients. Pis’ma Zh. Tekh. Fiz. 24, 6–12 (March 26, 1998)     

Formation of dense electron beams in a gun with a plasma anode based on a reflecting discharge

A method of obtaining low-energy, high-current electron beams in a gun with a plasma anode based on a reflecting discharge is proposed and implemented for the first time. Pis’ma Zh. Tekh. Fiz. 23, 42–46 (May 26, 1997)     

Trajectory tracing — a new method of studying the evolution of states of dynamic systems

A rapid method of trajectory tracing is proposedand described, which can clearly determine the points of period doubling bifurcations and provide clear information on the transformation of the states of a system in phase space. Pis’ma Zh. Tekh. Fiz. 25, 17–24 (January 12, 1999)     

Modulational method of eliminating the zero shift of a fiber ring interferometer induced by polarization nonreciprocity

A new method is proposed to eliminate the zero shift of a fiber ring interferometer induced by polarization nonreciprocity. This method is based on periodic modulation of the polarization state of nonmonochromatic radiation at the entrance to the interferometer ring system. Numerical estimates are given. Pis’ma Zh. Tekh. Fiz. 25, 78–82 (August 26, 1999)     

Extension of a model analysis of the degree of polarization of light

A theoretical approach is developed in which partially polarized radiation can be represented as a sum of coherent and incoherent components and also of the action of some imaginary device with time-dependent birefringence. This approach allows the Jones vector matrix method to be used for the calculations, which is important for theoretical calculations of the polarization state. Pis’ma Zh. Tekh. Fiz. 25, 74–78 (April 12, 1999)     

Use of a Sagnac interferometer for measurements of linear nonreciprocal birefringence in a transverse magnetic field

A method of measuring phase nonreciprocity in materials using a Sagnac interferometer is proposed and implemented in which the working point is shifted into the region of maximum slope of the interference pattern by means of an absorbing exit mirror. The principal advantage of this method over the laser technique is that there are no stringent constraints on the losses in the materials. This method was used for the first time at 0.83 _μm to measure the nonreciprocal linear birefringence in a LiIO₃ crystal in a transverse magnetic field. Pis’ma Zh. Tekh. Fiz. 23, 30–34 (October 12, 1997)     

Rearrangement of the shock wave structure in a decaying discharge plasma

A study has been made of the change in the structure of a shock wave in a decaying discharge plasma with Mach numbers between 1.2 and 2. A novel method is proposed to investigate the rearrangement of the shock wave structure under transient conditions. The times of the main processes responsible for this effect are determined. Pis’ma Zh. Tekh. Fiz. 23, 18–22 (April 12, 1997)     

Reconstruction of the mass distribution of charged particles in a periodic electric field

A method is proposed for determining the mass spectrum of a monochromatic precisely directed source by means of a plane-parallel capacitor with a sinusoidally time-dependent voltage on the plates. The mass spectrum is reconstructed from an integral equation that relates the current to the collector with the amplitude of the ac part of the voltage. Pis’ma Zh. Tekh. Fiz. 23, 1–7 (January 26, 1997)     

Influence of active oxygen on the superconducting properties of an yttrium ceramic investigated by a diffraction method

A diffractometric method of determining the amount of oxygen in intergranular media is described and the superconducting properties of YBaCuO ceramic are related to the intergranular oxygen content. Pis’ma Zh. Tekh. Fiz. 23, 13–18 (January 12, 1997)     

Exact solution of the problem of an equilibrium configuration of a two-dimensional charged liquid-metal droplet

A conformal mapping method was used to obtain exact solutions of the problem of the equilibrium shape of a charged two-dimensional liquid-metal droplet. It was found that when the perturbation amplitudes reach certain critical values, the regions occupied by the liquid ceased to be singly connected, which corresponds to the breakup of the droplet into parts. Pis’ma Zh. Tekh. Fiz. 25, 55–60 (December 12, 1999)     

Formation of heterogeneous molecules at the surface of metals in a mixture of protium and deuterium gases

An investigation was made of the formation of molecules of mixed hydrogen isotopes at the surface of tungsten. An original method is proposed to determine the chemisorption activation energy from the rate of desorption of heterogeneous molecules. Pis’ma Zh. Tekh. Fiz. 24, 41–44 (December 12, 1998)     

Determination of the uniformity of the carrier lifetime in a material from the profile of the amplitude spectrum of an ion detector

An analysis is made of charge transport in the neutral base of a p ⁺-n structure as a result of its diffusion to the boundary of the p-n junction under conditions where nonequilibrium carriers are generated by single α-particles. It is assumed that nonuniformity of the carrier lifetime (τ), described by a Gaussian distribution, exists over the area of the structure. The profile of the transported charge spectrum is calculated for these conditions and its correlation with the measure of nonuniformity τ is obtained. Since the tracks of the diffusing α-particles occupy an extremely small volume, recording them is equivalent to local probing of the material for τ. It is suggested that the calculated function should be used as a calibration function to determine the spread of τ values in materials. The method is tested on Si for a surface-barrier structure by recording 8.78 MeV π-particles. Pis’ma Zh. Tekh. Fiz. 24, 44–50 (March 12, 1998)     

GaAs nanolayers obtained by pulsed cooling of a saturated fluxed melt

A new method is proposed for obtaining nanolayers. The method is based on pulsed cooling of a saturated fluxed melt. The layers obtained were investigated with the aid of photoluminescence. The results show a high quantum yield of luminescence and therefore high quality of the layers grown. Pis’ma Zh. Tekh. Fiz. 23, 82–86 (September 12, 1997)     

Exact solution for the steady-state surface profile of a liquid metal in an external electric field

An analysis is made of the equilibrium profile of the free surface of a liquid metal in an external electric field neglecting gravitational forces. It is shown that a conformal mapping method can be used to find a wide range of exact solutions corresponding to the case of planar symmetry. Pis’ma Zh. Tekh. Fiz. 25, 79–83 (November 26, 1999)     

Simulation of iron fracture caused by a blast wave

A numerical simulation is made of the fracture of iron caused by a blast wave. The numerical method is described and results of calculations using a one-dimensional formulation of three qualitatively different explosion regimes are presented. Pis’ma Zh. Tekh. Fiz. 23, 33–39 (May 12, 1997)