Russian Physics Journal最新文献

A method for magnetic positioning of magnetic field sensors using a base station consisting of multiple source coils is proposed. It involves comparing the field measured by the magnetic sensors with the analytically calculated field generated by the base station. The base station field is calculated using the Biot-Savart-Laplace law It is also measured experimentally using a two-dimensional scanner. Then, the correction factors are calculated using the least squares method to calibrate the theoretical field with the measured field. The receiving magnetic sensor consists of 3 receiver coils forming a single sensor. The coils are oriented orthogonally to each other in the XOY, XOZ, and YOZ planes of the Cartesian coordinate system. The base station consists of 9 source coils, each of which emits a harmonic signal at a different frequency in the range of 10 to 20 kHz. This allows the signals to be separated during reception using a digital filter.

The experiments with an efficient generator of high-power, high-frequency L‑band pulses based on two nonlinear transmission ferrite lines connected in series and excited by one voltage pulse from a common SINUS-300 accelerator are described. The lines are manufactured using a new technology with corrugated central conductors and permanent magnets instead of solenoids. The central frequencies of the microwave pulses of each line are approximately 1 and 1.3 GHz, respectively. Helix high-voltage antennas are used as radiating antennas. The results of experiments with different geometric dimensions of the radiating antennas are presented. In one of the antennas, a high-voltage dielectric compound is used as an insulator. It is shown that the use of such a compound simplifies the design of some device units, without significantly affecting the efficiency of generating microwave oscillations.

The paper presents experimental and theoretical investigations of the generation of runaway electron beams in laboratory analog of red sprites. Experiments show that during the formation of plasma diffuse jets initiated in the capacitive discharge plasma having no contact with metal electrodes, runaway electron beams generate at air pressure of 0.4 and 1 Torr. It is shown that during a single voltage pulse, two current pulses of runaway electrons are recorded on a collector with the sub-nanosecond time resolution. The capacitive discharge is simulated in a quartz tube of the inner diameter 5 cm at the pulse voltage up to 20 kV and ≈6 ns (≈3 ns pulse edge) half-height duration. It is found that strong electric fields can occur at a 1 Torr air pressure in the quartz tube, which is sufficient for the generation of runaway electrons.

In March 2024, the relief staff of the Institute of Water and Environmental Problems of the Siberian Branch of the Russian Academy of Sciences and the Marine Hydrophysical Institute of the Russian Academy of Sciences carried out a comprehensive survey of bio-optical parameters of Zaliv Kamga (the northeastern part of Lake Teletskoye) as part of a mixed expedition. Statistical estimates of temperature and bio-optical parameters of Zaliv Kamga of Lake Teletskoye above and below the euphotic layer were obtained for three types of stations: ice, ice edge and open water. In addition, the daily stations were performed from ice in the area where the Kamga River flows into Zaliv Kamga. Measurements of temperature, photosynthetically active radiation, light attenuation coefficient at 660 nm, and chlorophyll‑a and organic matter fluorescence signals were taken every two hours. In all, 13 stations were completed. As a result of the conducted research, a daily cycle of bio-optical parameters of the aquatic environment was discovered and discussed in this work.

In this theoretical study, the nonrelativistic X‑ray wavelengths were calculated for elements with atomic numbers Z = (17–77), where the potential associated with each atom under study was calculated by reducing the nonrelativistic energy with regards to the central potential where the energy values were calculated. The optimal central potential obtained by the variational technique yields an integral equation that can be solved numerically for each atom. Good agreement is observed between the present calculations and the nonrelativistic Hartree–Fock calculations.

In this paper, we present results of theoretical study of the formation of an interference pattern by two mutually coherent vortex optical beams propagating in a turbulent atmosphere. Numerical simulation is used to study the propagation of optical beams in the atmosphere under conditions of weak atmospheric turbulence. The intensity distribution in interference patterns obtained at different distances from radiation sources is analyzed. A neural network is proposed to reconstruct the signal encoded by the topological charge value carried by laser beams from the interference pattern formed in the receiver plane.

Magnetic Fe-Ni-Co nanoparticles are synthesized by an electrical explosion of wires in an argon atmosphere. The average nanoparticle size is 66±1 nm. The nanoparticle show face centered cubic (fcc) and body centered cubic (bcc) structures. The observed grain size for the fcc phase is 64.1 and 44.8 nm for the bcc grains. The saturation magnetization and the coercivity are 82.3emu/g and 435 Oe, respectively. It is shown that the electrical explosion of wires can be used as a promising method for synthesizing the high-entropy alloy nanoparticles.

The inverse problem of determining the complex refractive index (CRI) of an aerosol particulate matter from measured radiation scattering characteristics is considered. The informativeness of polarization scattering phase functions in mixed-composition smokes when retrieving the CRI with allowance for its variability in different particle size ranges is studied numerically. The microphysical smoke model is chosen in accordance with work [1] and includes three particle size ranges with different CRI values. Errors of CRI retrieval are estimated as functions of optical uncertainties.

The paper investigates the scattering properties of cosmic dust particles using physical optics approximation, focusing on the identification of conditions under which the backscattered signal can be approximated by the specular component only. The analysis is given to the light scattering by irregular dust particles ranging in size from 5 to 100 μm, including pyroxene glass (n = 1.6847 + i0.0373) and graphite (n = 1.48 + i0.003). Geometrical parameters of the particles are measured for a statistically representative selection. It is found that for weakly absorbing materials like graphite, the backscattered signal becomes purely specular at the particle size exceeding 100 μm, whereas for strongly absorbing particles such as pyroxene glass, this occurs at 5 μm particles. Research findings are relevant for modeling stratospheric aerosol injection and interpreting lidar signals, where accurate optical models of cosmic dust are of great importance.

In contrast to line-of-sight optical communication, non-line-of-sight (NLOS) version allows data transmission between diversity of subscribers at various configurations of communication lines. We have designed the NLOS optical communication system operating at a wavelength of 1064 nm. In an evening field experiment, the system transmitted data through the smoke plume of a power plant emitted to a distance of 3.45 km with a symbol error rate no higher than 0.02.