Laboratory modeling of the interaction of electron beams with a magnetoplasma

We present the results of laboratory experiments in which the mechanisms of interaction of electron beams with whistler waves in a magnetoplasma are studied. Different mechanisms of whistler generation during the injection of a modulated electron beam in the plasma are studied, and the mechanism of conversion of the beam kinetic energy to radiation is demonstrated. The processes of whistler wave generation by the modulated beam at the ˇ Cerenkov and Doppler resonances are analyzed in detail. The excitation of whistler waves by means of a nonresonant mechanism of the transition radiation is studied.     

Structural and optical properties of solid-phase singlet oxygen photosensitizers based on fullerene aqueous suspensions

The relationship between the structural and photosensitizing properties of solid-phase particles of fullerene C₆₀ in aqueous suspensions is studied using the methods of absorption spectroscopy, electron spin resonance spectroscopy (ESR), X-ray diffraction, and spectrophotometry of solutions of singlet oxygen chemical traps—histidine in combination with p-nitrosodimethylaniline. Two new variants are proposed for obtaining aqueous suspensions of particles of solid-phase fullerene whose structures are disordered and whose degrees of amorphization are 67 and 40%, respectively. It is shown that an increase in the disorder of the structure of particles in suspensions and a decrease in their average size facilitate an increase in the formation efficiency of singlet oxygen by solid-phase fullerene presumably due to an in increase in the concentration of surface localized excitons.     

Laboratory studies of spectral features of stimulated electromagnetic emission during the ionospheric heating experiments

We present the results of laboratory studies of the formation of a number of spectral components of stimulated electromagnetic emission, which are related to the excitation of small-scale irregularities in the heated ionosphere. In the laboratory experiment, the small-scale irregularity was formed as a result of thermal self-channeling of short-wavelength quasielectrostatic oscillations in a magnetoplasma. Using the method of probing waves, it is experimentally shown that the trapping and waveguide propagation in a small-scale plasma irregularity are exclusively due to Langmuir waves, whereas the upper-hybrid waves with anomalous dispersion are not trapped into the irregularity. It is found that satellites shifted by about 1–2 MHz from the carrier frequency (700 MHz under the experimental conditions) are formed in the Langmuir wave spectrum during the thermal self-channeling. Two mechanisms of generation of spectral satellites have been detected. The first (dynamic) mechanism is observed during the formation of a small-scale irregularity with rapidly increasing longitudinal size. In this case, one low-frequency satellite is excited in the trapped-wave spectrum. The mechanism of the formation of this satellite is apparently related to the Doppler shift of the frequency of the Langmuir waves trapped inside the irregularity. The second (stationary) mechanism is observed in the case of a developed irregularity where its shape is close to cylindrical. In this regime, the trapped-wave spectrum has two symmetric spectral satellites, namely, high- and low-frequency ones. It may be hypothesized that the generation of these satellites is due to scattering of trapped Langmuir waves from drift oscillations of the irregularity.     

Cardinality of the Set of Delta–Closed Classes of Functions of Multi–Valued Logic

A closure under composition operation and weak version of inversion operation is considered on the set of functions of k–valued logic. The cardinality of the set of all such closed classes is calculated.     

Multiwatt optically pumped ammonia laser operation in the 12–13 μm

Design and operating caracteristics of high pulse repetition rate NH₃ laser producing up to 20 W of average output power are described. The NH₃ laser, operating in the 12–13 μm region was optically pumped with a high pulse repetition rate TEA CO₂ laser. Dependences of the NH₃ laser output on the pump energy, ammonia and buffer gas pressures and pulse repetition rate have been studied. The conversion efficiency of up to 16% has been received.     

Buildup of color centers in electron-irradiated phosphate glass

Individual Gaussian-shaped bands are isolated in optical absorption spectra using a computer and their parameters are determined. An increase in the concentration of both types of color centers with increasing integral electron flux is calculated using the Smekal formula. Two sections are isolated in the build-up kinetics for the centers. The concentration of color centers at 3.0 eV and 2.4 eV are related to each other.     

Charging of inorganic glasses during irradiation and the energetics of their structure

Conclusions The energetics of the glass structure glasses characterizing the magnitude of the cation-oxygen bond constitutes the key factor which determines the quantity of charge stored. In the successive replacement of cation-modifiers, most charge is stored in those glasses in which the lowest concentration of hole color centers is produced. In the event of a percentage change in the content of the cation-modifier in the glass structure, most charge is stored in those glasses that lie closest to the metaphosphate line.A law of charge storage in phosphate glasses has been established. The kinetics of charge storage is more complex: a rapid increase in the quantity of charge stored is observed in the first stage of storage, whereas in the second stage the quantity of charge stored is observed to decrease slowly at large doses. Analysis of the curves indicates two processes occurring in the glasses during irradiation.The mechanism of neutralization of electrically active centers consists in a neutral P₂O₇ complex being formed from the charged radicals PO ₃ ^– and PO ₄ .Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 60–65, July, 1977.     

Discharges and mechanoelectrical phenomena in charged glasses

Conclusions In high-resistance solid dielectrics (with resistances of 10¹² · cm or higher, when they are irradiated with electron beams, spontaneous electric discharges are observed while the irradiation is occurring. The discharges occur at defects in the surface and develop in the layer within which the charged particles are distributed.When the charged particles are distributed in the surface or near-surface layer of the dielectric, the discharge may be initiated close to the charged surface by a grounded metal needle, even some time after the irradiation. After long storage and self-dis charge of the surface layer of the irradiated dielectric or compensation of the surface charge, discharge of the charge stored in the depth of the dielectric can occur by scratching the surface or pricking it with a needle. When the charge lies deep inside the dielectric, a brush discharge occurs when a strong shock is applied to the surface of the dielectric using a grounded needle.In all the above cases initiation of an electric discharge in the solid dielectric occurred by mechanoelectrical phenomena of direct conversion of mechanical energy into electrical energy with a high field strength. These phenomena occur in solid dielectrics with a defect structure.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 40–46, February, 1977.