Extremely-high-energy cosmic rays: Prospects for research with space-based detectors

The experimental study of high-energy cosmic rays at SINP is based on the legacy left by S.N. Vernov. An abrupt change (cutoff) of the cosmic-ray energy spectrum in the range of ultrahigh energies, ∼5 × 10¹⁹ eV, was predicted in the works of Greisen-Zatsepin-Kuzmin (GZK). In these and in recent works, it was hypothesized that the shape of the spectrum beyond the GZK limit is related to the evolution of the Universe at the earliest stage of its development, which arouses special interest in studying such extremely high energies. At the same time, experimental study of cosmic-ray particles with such high energies encounters difficulties in connection with their extremely low intensity. To develop a method of particle detection on a maximum area of the order of the Earth’s disk area, in recent years it has been suggested to move from ground-based to space-based detectors. The program of space experiments to study extremely-high-energy cosmic-ray particles is discussed.     

Recurrent fast particle enhancements observed from KORONAS-I

Enhancements of protons with energiesE _p =1–4.5 MeV were observed from the KORONAS-I satellite in the period from March to June 1994. They represent part of a long series of corotating particle enhancements registered by the ULYSSES spacecraft outside the ecliptic plane. An about 5-day nearly constant shift between the maximum times was recorded by the two space vehicles. The assumptions of acceleration area localization and fast proton propagation conditions in the heliosphere are discussed on the basis of a joint analysis of the results presented here and the related experimental data.     

The geometrical optics approach for multidimensional liquid crystal cells

We present an approach based on the geometrical optics approximation (GOA) for analysis of liquid crystal cells whose director varies in more than one spatial dimension (multidimensional liquid crystal cells). The GOA is applied to calculate light transmittance and far field diffraction patterns for two- and three-dimensional nematic liquid crystal films. Important features of the GOA, such as a method of eliminating non-convergence problems that can occur during the iterative numerical solution of the equations for the amplitudes of the electromagnetic field, are described. We compare the results obtained from the GOA with those produced by the quasi-one-dimensional Jones calculus and the beam propagation method, where the latter is applicable. It was found that the refraction (or ray bending) effects, produced by the GOA, are more important than effects of diffraction and light scattering, which means that the GOA (unlike the Jones calculus) is accurate for the considered type of liquid crystal cells, whose director varies on the micron scale. The GOA is about as fast as the Jones method and is applicable for calculating optical properties of liquid crystal cells with any number of dimensions of director variations.     

Some characteristics of relief formation on photothermoplastic carriers used in double-exposure interferometry

An analysis is made of the main trends in the development of a surface relief on photothermoplastic carriers of optical information used to record double-exposure holographic interferograms. It is shown that high-quality interferograms require recording conditions (taking into account the composition of the material and the heating temperature of the thermoplastic carrier layer, as well as the parameters of the sensitizing corona discharge) where the surface of the photothermoplastic carrier can be treated in the equipotential approximation. Zh. Tekh. Fiz. 67, 76–78 (August 1997)     

KLYPVE/TUS space experiments for study of ultrahigh-energy cosmic rays

The KLYPVE space experiment has been proposed to study the energy spectrum, composition, and arrival direction of ultrahigh-energy cosmic rays (UHECR) by detecting from satellites the atmosphere fluorescence and scattered Cherenkov light produced by EAS, initiated by UHECR particles. The TUS setup is a prototype KLYPVE instrument. The aim of the TUS experiment is to detect dozens of UHECR events in the energy region of the GZK cutoff, to measure the light background, to test the atmosphere control methods, and to study stability of the optical materials, PMTs, and other instrumental parts in space environment.     

Diagrams of critical equilibrium for brittle bodies with sharp flaws

Certain forms of the stress-intensity factors close to the tips of sharp flaws (plane problem) are used as the basis of a method for plotting critical equilibrium diagrams for brittle bodies with flaws in the form of pointed cavity-cracks [5]. Concrete examples are discussed, mainly in the context of such diagrams, for a brittle body weakened by a circular cavity flaw with a crack leaving the edge of the flaw. Determination of the stress-intensity factors for this problem is based on approximate solution of an integral equation by the method of collocations. Plots of some familiar diagrams are also analyzed.Translated from Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Vol. 11, No. 3, pp. 98–104, May–June, 1970.     

Fluxes of GCR and SCR iron nuclei in the international space station orbit

The anticipated flux of iron nuclei and ions in the energy interval 26–168 MeV/nucleon in the orbit of the international space station (ISS) during the exposure of the PLATAN-M dielectric track detector from January 26, 2002, to August 3, 2004, has been estimated. The calculation is based on the data obtained using the SIS spectrometer onboard the ACE space station and the last version of the model describing the penetration of charged particles into the Earth’s magnetosphere. The time variations in the GCR iron nuclei intensity in the ISS orbit during solar cycle 23 have been obtained using the data of the PLATAN-4 and PLATAN-5 earlier experiments onboard the Mir space station.