Software implementation of orbit construction methods in the CR3BP
Software implementation of orbit construction methods in the CR3BP
T. A. Syachina, A. G. Rudnitskiy
This paper presents a software implementation of methods for accurate calculation of orbital parameters for near-Earth space, as well as for the vicinity of the Lagrange points. The program is based on modern mathematical models and algorithms providing high accuracy and efficiency of calculations. Various perturbing factors are taken into account and the possibility to model spacecraft motion in complex gravitational conditions is implemented. The results of the program are compared with known software solutions for ballistic and navigation calculations.
Show AbstractAnalysis of hystersis behavior of the lock-in range in a Zeeman ring laser
Analysis of hystersis behavior of the lock-in range in a Zeeman ring laser
M. E. Grushin$^2$, E. G. Lariontsev$^1$, I. I. Savel'ev$^2$, E. V. Soukhov$^2$
Broad hystersis area of the lock-in range in a Zeeman ring laser till now were not described theoretically. In this paper we propose a new model accounting an additional coupling of the counterpropagating waves due to their diffraction on the gratings induced in the cavity mirrors. Hysteresis area of the lock-in range have been studied experimentally.
Show AbstractMorphological methods for estimating the relative time shift of infrasound signals
Morphological methods for estimating the relative time shift of infrasound signals
A. F. Idrisov, A. I. Chulichkov
The present work is devoted to solving the problem of estimating the relative time delay of infrasound signals propagating from a pulse source along different trajectories in a layered homogeneous atmosphere. To solve the problem, morphological methods of signal analysis are used, developed at the Department of Mathematical Modeling and Computer Science, Faculty of Physics, Lomonosov Moscow State University. The methods are applied to the infrasound signals data recorded by barographs located at different points on the Earth’s surface. The time delay of the signals from different barographs allows us to estimate the direction of arrival of the sound wave, which allows us to further determine the position of the signal source and study the structure of the atmosphere.
Show AbstractFacility for measurement of sky background variations in the infrared at the Caucasian Mountain Observatory of the SAI MSU
Facility for measurement of sky background variations in the infrared at the Caucasian Mountain Observatory of the SAI MSU
I. A. Komarova$^1$, A. M. Tatarnikov$^2$, S. G. Zheltoukhov$^3$
The description of the device constructed at the SAI MSU based on a commercial infrared light-sensitive module for the study of the sky background brightness (SBB) distribution in the infrared is presented. The procedure of observations with the instrument and the algorithm for accounting for the contribution of the instrumental background to the total signal are described. The results of measurements of the SBB at the Caucasus Mountain Observatory at wavelengths of 3.7~$\mu$m and 4.7~$\mu$m carried out in December 2024 are presented. An estimate of the SBB at zenith corresponding to the star $7.3^{\rm m}$ at 1 arcsec$^2$ of the sky is obtained.
Show AbstractCombining chiral optical Tamm states into one mode of a hybrid structure
Combining chiral optical Tamm states into one mode of a hybrid structure
N. V. Rudakova$^{1,2}$, S. Y. Vetrov$^{1,2}$, I. V. Timofeev$^{1,2}$
The excitation conditions and effective control possibilities are investigated for two coupled chiral optical Tamm states arising at boundaries of a crystalline liquid crystal coupled with polarization-preserving anisotropic mirrors. Numerical modeling has shown that varying the parameters makes it possible to control the magnitude of transmission coefficient of the structure, the optimization of the spectral characteristics, as well as the profile of the local field intensity. In this case, the polarization of the incident light has a significant effect on the excitation efficiency. It is shown that the hybrid mode of two chiral optical Tamm states smoothly transforms into a single Fabry-Perot mode in the process of increasing coupling between them.
Show AbstractFe$_{100-х}$Zr$_x$ films ($x = 6-13$ at. %): relationship between phase-structural state and magnetic parameters
Fe$_{100-х}$Zr$_x$ films ($x = 6-13$ at. %): relationship between phase-structural state and magnetic parameters
D. M. Gridin$^{1,2,3}$, E. V. Harin$^4$, V. A. Tejetov$^4$, G. S. Usmanova$^4$, E. N. Sheftel$^4$, A. B. Granovsky$^{1,5,6}$
The results of measurements of hysteresis loops of Fe$_{100-х}$Zr$_x$ films ($x = 6-13$) are presented both in the initial state after their preparation by ion beam deposition and after annealing in vacuum for 1 hour at 300 and 500 ° C. The measurements were performed on a vibrating magnetometer Lake Shore 7407 in magnetic fields up to 16 kOe at room temperature. An analysis of the data obtained by correlation magnetometry using the model of random magnetic anisotropy has shown that the magnetic properties of films are determined by the coexistence of amorphous and nanocrystalline structures, the volume fractions of which depend on the Zr content and the annealing temperature. For all films, even when the ferromagnetic fraction is several percent, a long-range magnetic order is observed, which is explained by the exchange interaction between neighboring ferromagnetic grains grouped into stochastic domains that are isolated from each other by a paramagnetic amorphous phase. The main magnetic parameters of the microstructure of the films are determined.
Show AbstractMethod for optimizing acceleration structures for applied purposes using genetic algorithms
Method for optimizing acceleration structures for applied purposes using genetic algorithms
M. A. Borisov$^{1,2}$, V. I. Shvedunov$^{1,2}$
The article provide a description of the method of optimizing the structures of linear electron accelerators operating in the standing wave mode based on the genetic method, using the example of optimizing a medical accelerator.
Show AbstractMössbauer Study of the Thermally Induced Evolution of the Crystalline and Magnetic Structure of Magnesium Ferrite Nanoparticles
Mössbauer Study of the Thermally Induced Evolution of the Crystalline and Magnetic Structure of Magnesium Ferrite Nanoparticles
T. Yu. Kiseleva$^1$, V. S. Rusakov$^2$, L. A. Lebedev$^3$, Y. A. Khvashevskaya$^3$, V. I. Popkov$^3$
This study presents a Mössbauer spectroscopic investigation of the thermally induced evolution of the crystalline and magnetic structure of magnesium ferrite (MgFe$_2$O$_4$) nanoparticles synthesized via solution combustion, followed by sequential annealing in the 400–800 °C range. The as-prepared product was found to be X-ray amorphous while maintaining a stoichiometric composition, allowing isolated analysis of structure formation during heat treatment. A combination of $^{57}$Fe Mössbauer spectroscopy (performed at 300 K and 80 K) and X-ray diffraction was employed to track the crystallization process and magnetic state transitions in the nanoparticle ensembles. Samples annealed at temperatures up to 600 °C exhibit superparamagnetic behavior associated with small crystallite sizes (below ~16 nm). A critical transformation occurs between 600 and 700 °C, where a sharp increase in crystallite size (~24 nm) leads to the emergence of magnetically ordered domains and relaxation-dominated Mössbauer spectra. Further annealing at 800 °C results in structural stabilization and a pronounced reduction in spin relaxation rates, as evidenced by narrowing hyperfine lines and size-related shifts in hyperfine parameters. These findings demonstrate a strong correlation between thermal treatment, structural ordering, and the magnetic response of MgFe$_2$O$_4$ nanoparticles. The study highlights thermal annealing as a key tool for tuning nanoscale magnetic properties through controlled phase development.
Show AbstractModeling and processing of correlated measurements in satellite gradiometry
Modeling and processing of correlated measurements in satellite gradiometry
V. E. Zharov
In this paper, the issue of processing correlated measurements is considered. It is assumed that the true signal is distorted by the device, which, in fact, is a filter with a given amplitude-frequency response. As a result, the signal spectrum changes in the frequency domain, and in the time domain, the value of the measured signal at time $t_i$ depends on the previous values of $t_{i-1}, t_{i-2}, \ldots$. This means that when processing measurements, it is necessary to know and be able to reverse the covariance matrix, which is not diagonal, and may have large sizes. In this case, direct conversion of the matrix is impossible. Therefore, an original method for calculating the inverse covariance matrix and measurement de-correlation is proposed for processing correlated measurements. The developed method is supposed to be used to process the gradiometric data obtained during the GOCE mission and calculation of the spherical harmonic coefficients of the classical series expansion of the Earth’s gravitational field.
Show AbstractCharacteristics of FeSe$_{0.5}$Te$_{0.5}$ films on an amorphous substrate
Characteristics of FeSe$_{0.5}$Te$_{0.5}$ films on an amorphous substrate
A. V. Petrov$^1$, O. V. Snigirev$^1$, A. G. Maresov$^1$, Yu. V. Blinova$^2$, N. V. Porokhov$^3$, D. A. Chareev$^{4,5}$, A. V. Varlashkin, A. Yu. Tsvetkov
For FeSeTe films on an amorphous dielectric substrate, the surface morphology and elemental composition were investigated. The measured root-mean-square roughness values of the film surface were 4–6 nm in a 1×1 μm² area and 7–10 nm in a 10×10 μm² area. The determined elemental composition, FeSe$_{0.5}$Te$_{0.5}$, was found to be close to the stoichiometric ratio. Estimates of the upper critical fields were obtained: Hc2∥ab(0) ≈ 68 T and Hc2⊥ab(0) ≈ 51 T for different orientations of the magnetic field relative to the crystallographic planes of the film. The corresponding anisotropy value γ of the film properties is about 1.3 and is comparable to the results for such films on single-crystal substrates. The coherence lengths were found to be ξab(0) ≈ 2.5 nm and ξc(0) ≈ 1.9 nm. The critical current density, measured by both contact and contactless methods, was 2.5×10⁴ A/cm² and 6×10⁴ A/cm², respectively, at 2 K. Estimates of the vortex activation energy U(H,T) and the pinning force density were also obtained.
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