Issue 3, 2026
Greenhouse effect on planets and moons of the Solar System
Greenhouse effect on planets and moons of the Solar System
A. V. Aliakin$^{1,2}$, A. V. Karnaukhov$^3$, M. E. Prokhorov$^2$
The article provides an overview of the greenhouse effect on Earth, as well as on various planets and moons in the Solar System. The history of the study of this phenomenon is described. Various types of greenhouse effect are considered. References to key scientific works on all the listed topics are given. The comparative analysis provided may give an idea of possible atmospheric processes and conditions on the surface of Earth-like exoplanets.
Show AbstractPhotonuclear Reactions with Charged Particle Emission: Prospects for Medical Isotope Production
Photonuclear Reactions with Charged Particle Emission: Prospects for Medical Isotope Production
M. V. Zheltonozhskaya$^1$, P. D. Remizov$^1$, A. P. Chernyaev$^1$, K. A. Andrei$^1$, V. V. Varlamov$^1$, V. I. Shvedunov$^1$
Thisreviewfocusesonmethodsforproducingpromisingmedicalradionuclidesusingphotoproton nuclearreactions.Primaryattentionisgiventotheranosticisotopes,suchaslutetiumisotopes 177Lu and rhenium isotopes 186,188,189Re, which can be obtained with high radionuclidic purity. Of particular note is an innovative scheme for producing the diagnostic positronemitting radioisotope zirconium 89Zr via photoproton reactions on molybdenum, which ensures high radionuclidic purity of the preparation and enables production organized on the principle of a generator system. The leading role of the D.V. Skobeltsyn Institute of Nuclear Physics at Lomonosov Moscow State University in the development of this field in Russia is highlighted. This work encompasses fundamental research on photonuclear fission, obtaining reliable cross-sections for photonuclear reactions, and their subsequent application in medical technologies and clinical practice.
Show AbstractThe fast method of bolus shape calculation in the ion beam therapy planning system
The fast method of bolus shape calculation in the ion beam therapy planning system
A. A. Larionov$^1$, F. R. Studenikin$^2$, O. P. Yushchenko$^1$
The method for calculating bolus shape in radiation therapy for wide ions list and different bolus material types is presented. Currently any ion in the range H-Ca can be used as well as materials list consists of polistirol, PLA and aluminium. The lists of ions and materials can be extended. This method is implemented as a component of a planning system for the ion beam therapy center being developed at the NRC “Kurchatov Institute” – IHEP. An example of bolus calculation for a real patient and verification results using detailed modeling in GEANT4 are presented.
Show AbstractA Simulation Approach to Evaluate the Effect of Increasing Energy on Relationship Between Dosimetry Quantities
A Simulation Approach to Evaluate the Effect of Increasing Energy on Relationship Between Dosimetry Quantities
H. Al Kanti
The radiation dosimetry quantities are used to calculate the operational and protection quantities by ICRU and ICRP. In the fields of radiation protection and medical physics, accurately differentiating between Kerma and Absorbed Dose is fundamental, especially in interface regions where electronic equilibrium is disrupted. This study investigates the impact of increasing incident photon energy on the relationship between these two quantities within a water phantom, providing a high-precision quantitative analysis. A simulation approach DOSRZnrc code was employed to compute absorbed dose and kerma for mono-energetic photons at energies 0.5, 1, 10, 25, 30 MeV and spectrum Co-60 and Cs-137 with the number of histories optimized to ensure a relative statistical uncertainty of less than 0.5\%. While the qualitative behavior of these quantities is established in classical physics, this research offers significant added value by providing updated reference datasets that bridge the gap between theoretical textbook models and modern clinical practice. The difference between absorbed dose and kerma are increases with increasing energy. The ratio between absorbed dose and kerma at the medium surface is equal to 0.99, 0.12 at energies 0.5 and 30 MeV. Whereas the ratio between absorbed dose and kerma at maximum dose is equal to 0.99, 0.88 at energies 0.5 and 30 MeV. The study’s significance lies in its precise determination of Transient Charged Particle Equilibrium (TCPE) distances, ensuring higher accuracy in absorbed dose estimations for biological media and radiotherapy treatment planning.
Show AbstractRecovering of gaps in multivariate time series using methods of mathematical statistics and machine learning
Recovering of gaps in multivariate time series using methods of mathematical statistics and machine learning
V. S. Aleshnovskii$^1$, V. K. Avilov$^2$, P. V. Golubtsov$^1$, J. A. Kurbatova$^2$, O. A. Kuricheva$^2$, D. A. Makeev$^1$, P. A. Fadeeva$^1$, A. I. Chulichkov$^{1,3}$, N. E. Shapkina$^1$
The research focuses on multivariate time series of geophysical parameters. During the study, statistical and machine learning methods were employed to recover missing data. The following results were achieved: for the $CO_2$ concentration series at a height of 30 meters, the ARIMAX model demonstrated the lowest RMSE and MAE metrics, taking only 2.3 seconds for recovery, which is significantly faster compared to the LSTM (251 sec.) and GRU (160 sec.) neural network models. The air temperature data were most effectively recovered using the recurrent neural network model GRU. The results indicate that ARIMA family models are more suitable for data recovery when correlated parameters are present, whereas GRU-based neural networks are preferable in other cases. These conclusions can be utilized to enhance data recovery methods in multivariate time series analysis.
Show AbstractHelmholtz Free Energy in the Two-Dimensional Ising Model with Defects
Helmholtz Free Energy in the Two-Dimensional Ising Model with Defects
V. V. Binkovskii, S. D. Mostovoy
In this paper, the influence of point defects such as vacancies on the thermodynamic properties of the two-dimensional Ising model is investigated. The main attention is paid to comparing two approaches to describing the system: the traditional analysis of internal energy E and a more complete analysis of the Helmholtz free energy F and entropy S. Using Monte Carlo methods - the Metropolis algorithm and the Wang - Landau algorithm - the temperature dependences of the changes in these quantities upon the introduction of defects are calculated. It is established that the interaction between defects is attractive with a effective radius of d ~ 3. It is shown that in the phase transition region, the free energy behaves as a continuous monotonically decreasing function of temperature, while the internal energy exhibits a singularity caused by the behavior of entropy. The possible dynamics of defects is investigated by comparing the energy of different configurations; a tendency towards defect clustering at temperatures above the critical one is observed. A comparative analysis of the accuracy and computational efficiency of both approaches is carried out.
Show AbstractPath integral for a charged quantum particle in a magnetic field
Path integral for a charged quantum particle in a magnetic field
K. A. Lursmanashvili$^1$, V. V. Chistiakov$^2$
The quantum-mechanical problem of a charged particle in a magnetic field is considered. Transformations of the functional integration variable of a specific type are analyzed with respect to their action on the Wiener measure. It is shown that the functional integrals for a particle in a uniform magnetic field are equivalent to those for a free particle.
Show AbstractReal-Time Accumulation of Calibration Information and Its Application to Optimal Control with Inaccurate Predictive Models
Real-Time Accumulation of Calibration Information and Its Application to Optimal Control with Inaccurate Predictive Models
E. M. Churakov$^1$, P. V. Golubtsov$^1$
We consider the problem of optimal control of a dynamical system under inaccurate knowledge of its parameters. An approach to continuous real-time parameter calibration is proposed, based on the accumulation of calibration information of a special form for model predictive control. This approach does not require storing the full data history and allows the calibration information to be updated and the parameters to be recomputed at each control step. The algorithm developed in the paper is illustrated on the problem of motion of an object in a viscous medium. Numerical simulation results demonstrate a significant improvement in control quality after parameter calibration: elimination of oscillations, reduction of overshoot, and decrease in the objective function values. An important feature of the proposed approach is the ability to refine the model parameters without interrupting the normal operation of the system. A modification of the algorithm is also considered that provides gradual forgetting of calibration information, making it applicable in the presence of parameter drift.
Show AbstractHeat capacity at constant pressure at the saturation line of argon
Heat capacity at constant pressure at the saturation line of argon
P. N. Nikolaev
In this work, the main characteristics of the liquid–gas phase transition in argon are calculated based on the correlation cell-cluster decomposition. On the saturation curve, the heat capacity at constant pressure was calculated on the saturation curve for both liquid and gas. There is a monotonic increase in heat capacity at constant pressure with increasing temperature. This fundamentally distinguishes the behavior of heat capacity on the saturation curve from its behavior on the crystallization and melting curves. A comparison of theoretical and experimental data was performed, and good agreement was found.
Show AbstractOn Planar Perturbations in Vertically Stratified Keplerian Disks in a Uniform Magnetic Field
On Planar Perturbations in Vertically Stratified Keplerian Disks in a Uniform Magnetic Field
K. Yu. Parusov
We perform a local modal analysis of the magnetorotational instability (MRI) in the midplane of a thin Keplerian accretion disc with a polytropic vertical density stratification. To obtain an analytic solution, we adopt the approximation $\partial/\partial r=0$ for all perturbations and consider planar adiabatic perturbations of an incompressible fluid with $u_z=0$. We derive an analytic closed-form dimensionless dispersion relation, determine the unstable intervals of the vertical wavenumber $k_z$, and identify the MRI-unstable branch. We show how the unstable wavenumber ranges and the extremal values of the dispersion curve depend on the strength of the background magnetic field.
Show AbstractTemporal analysis of the SOL2015-08-21 flare radiation, theoretical calculation of observed fluxes in the calcium, hydrogen, and helium lines. Inhomogeneity of the flare structure and the role of plasmoids
Temporal analysis of the SOL2015-08-21 flare radiation, theoretical calculation of observed fluxes in the calcium, hydrogen, and helium lines. Inhomogeneity of the flare structure and the role of plasmoids
Yu. A. Kupryakov$^{1,3}$, K. V. Bychkov$^1$, V. A. Maliytin$^1$, A. B. Gorshkov$^1$, O. M. Belova$^2$, M. -. Barta$^3$
We observed a M1.4 class flare in the active region NOAA 12403 using the Horizontal Solar Array for Solar Surveys (HSFA-2) at the Ond\v{r}ejov Observatory in the spectral lines of calcium, helium, and hydrogen, as well as using two radio telescopes. The active region remained unchanged for several days, located in a region of a strong magnetic field. It was a typical bipolar region consisting of a group of spots, pores, and bright flocculi. After processing the spectra, we determined the integrated radiation fluxes in the H$\alpha$, H$\beta$, H$\varepsilon$, H~CaII and IR CaII (8542 \AA{}), HeI D3 lines. Then, using a model of heated homogeneous gas layers, we calculated theoretical fluxes taking into account the physical conditions in the chromosphere, including self-absorption in the spectral lines. To explain the observed fluxes, we had to consider three gas layers oriented perpendicular to the line of sight, each with its own individual parameters. One of them is very extended, while the other two are thin, indicating that the flare plasma is highly inhomogeneous.
Show AbstractGEODYNAMICS OF THE EASTERN SEGMENT OF THE GREATER CAUCASUS BASED ON GNSS OBSERVATIONS
GEODYNAMICS OF THE EASTERN SEGMENT OF THE GREATER CAUCASUS BASED ON GNSS OBSERVATIONS
A. P. Mironov$^1$, V. K. Milyukov$^1$, A. N. Ovsyuchenko$^2$, A. S. Larkov$^2$, K. M. Khubaev$^3$
This paper presents the results of a comprehensive study of the geodynamic features of the eastern segment of the Greater Caucasus, based on long-term quasi-continuous satellite geodetic observations at 28 regional GNSS stations, as well as summarized data on the seismicity and geotectonics of the region. The study results are interpreted within the context of regional seismotectonics. The research findings provide insight into the current geodynamic setting of the eastern segment of the Greater Caucasus. Quantitative estimates of the kinematics of the main regional tectonic structures are obtained.
Show AbstractFeatures of fission fragment spin formation in complete fusion reactions of deformed nuclei
Features of fission fragment spin formation in complete fusion reactions of deformed nuclei
V. A. Drozdov$^2$, D. O. Eremenko$^{1,2}$, O. A. Yuminov$^2$
Within the framework of a dynamic model, an analysis of the energy dependencies of the average spins of fission fragments formed in complete fusion reactions of deformed nuclei has been performed. The parameters of the dynamic model were determined based on the conditions for the best description of experimental data on average fission fragment spins for the reactions $^{12}$C$+$$^{232}$Th, $^{16}$O$+$$^{209}$Bi, $^{12}$C$+$$^{209}$Bi and $^{16}$O$+$$^{232}$Th. Special attention is given to the influence of the initial distributions for the components of the total angular momentum of the compound nucleus formed in the entrance channel of the reaction on the spin formation process of the fission fragments. The entrance channel effect is considered using the example of the ${12}$C $+$ $^{236}$U and $^{13}$C $+$ $^{235}$U reactions, , which lead to the formation of the same compound nucleus, $^{248}$Cf. It is shown that at sub-barrier collision energies, noticeable differences in the behavior of the average fission fragment spins should be observed for different entrance channels of the fusion reaction
Show AbstractStudy of the subsurface temperature maximum in meromictic reservoirs of the Kandalaksha Bay based on mathematical modeling
Study of the subsurface temperature maximum in meromictic reservoirs of the Kandalaksha Bay based on mathematical modeling
I. N. Ivanova$^1$, A. V. Klenin$^2$, V. M. Stepanenko$^3$, E. D. Krasnova$^4$, D. A. Voronov$^5$
In the coastal meromictic lakes Kislo-Sladkoe and Trekhtsvetnoe (the White Sea, the Kandalaksha Bay), the temperature regime was studied using the generalized one-dimensional model of thermodynamic, hydrodynamic, and biogeochemical processes, LAKE. Special attention was paid to the process of formation of the Mid-depth temperature maximum (TeM). The model demonstrated its ability to realistically reproduce various physical phenomena in the annual cycle of the water body's life, including the TeM, autumn cooling, and winter temperature maximum. For the first time, the following factors have been suggested to have a key influence on the characteristics of the TeM and its presence: the salinity of the lake's layers relative to each other, the salinity gradient exceeding 10-13 PPT/m, and the location of the maximum salinity gradient relative to the surface of the water body. The data obtained from the modeling have been compared with field measurements.
Show AbstractSeiches in Kuril Lake Stimulated by the 2025 Mw 8.8 Kamchatka Earthquake
Seiches in Kuril Lake Stimulated by the 2025 Mw 8.8 Kamchatka Earthquake
M. A. Nosov$^{1,2}$, D. N. Valeeva$^1$
Using wave phenomena initiated in Kuril Lake by the 8.8 Mw Kamchatka earthquake as an example, the formation of seismogenic seiches in enclosed bodies of water on land is analyzed. Within the framework of linear potential wave theory, it is shown that the primary contribution to the amplitude of seiche oscillations comes from the first few eigenmodes, which can be considered long-wavelength. The contribution of higher eigenmodes decreases inversely proportional to the square of the frequency. Seiches generated by the 8.8 Mw Kamchatka earthquake in Kuril Lake were numerically simulated using linear shallow-water equations. It was shown that in narrow bays and straits, lake level fluctuations could reach 5 m, and current velocities could reach 2 m/s. The numerical results for the “Kordon Ozerny” point (2.3 m, 1.1 m/s) are consistent with eyewitness accounts.
Show AbstractElectronic properties of the CsPb$_{1-x}$Mn$_{x}$Cl$_3$ solid solution with a perovskite structure
Electronic properties of the CsPb$_{1-x}$Mn$_{x}$Cl$_3$ solid solution with a perovskite structure
E. D. Rubtsova$^{1,2}$, A. N. Vasil'ev$^2$, I. A. Kamenskikh$^1$, I. N. Shpinkov$^{1,2}$
Within the framework of DFT and DFT+U methods, the electronic structure and density of states of solid solutions CsPb$_{1-x}$Mn$_x$Cl$_3$ with the perovskite structure ($x$ = 0, 0.125, 0.25) were calculated. Crystals were characterized as dielectrics with direct bandgaps. With increasing manganese concentration in the compound ($x$), the following trends were revealed: a decrease in the perovskite lattice constant, an increase in the band gap of the solid solution, and an increase in the influence of Mn states on the formation of the valence band top and the conduction band bottom. The three-dimensional Mn states form defect subbands that create an additional emission channel for the recombination of excited carriers. The calculated results are consistent with the experimental data available in the literature.
Show AbstractSequential ion-beam and cluster-ion surface processing of YBa2Cu3O7-δ
Sequential ion-beam and cluster-ion surface processing of YBa2Cu3O7-δ
A. V. Nazarov$^{1,2}$, D. S. Kireev$^2$, A. N. Rattsev$^{1,2}$, A. A. Tatarintsev$^2$, M. A. Ovchinnikov$^1$, A. M. Borisov$^{1,3}$, N. N. Andrianova$^{1,3}$, P. N. Degtyarenko, A. A. Shemukhin$^{1,2}$
This paper presents the results of sequential irradiation of the YBa₂Cu₃O₇₋δ superconducting layer of a 2G HTS tape using atomic and cluster argon ions. It is shown that two-stage irradiation with atomic ions at a grazing incidence angle of 85° removed a oriented crystallite protrusions, significantly reducing the RMS roughness. Subsequent surface treatment with cluster ions at normal incidence results in smoothing of the surface topography in the spatial frequency range from 0.5 µm⁻¹ to 10 µm⁻¹. It is worth noting that, within the framework of this method, the depth of the modified layer does not exceed 10–20 nm, which indicates that no structural damage is introduced into the bulk of the superconducting film.
Show AbstractTemperature dependence of the macroscopic superconducting order parameter in Ba0.45K0.55Fe2As2 pnictides of a doped composition
Temperature dependence of the macroscopic superconducting order parameter in Ba0.45K0.55Fe2As2 pnictides of a doped composition
S. N. Pontis$^1$, S. A. Kuzmichev$^2$, A. D. Ilina$^1$, I. A. Nikitchenkov$^{1,2}$, T. E. Kuzmicheva$^1$, I. V. Morozov$^3$, V. A. Grinenko$^4$
This study investigates single crystals of the overdoped iron pnictide Ba0.45K0.55Fe2As2 with Tc ≈ 29 K. The current-voltage characteristics of planar mechanically adjustable contacts on a microcrack at various temperatures were obtained and analysed. The dependence of the bulk critical supercurrent on temperature in a zero magnetic field has been successfully described within the framework of a two-zone model, which has allowed the estimation of the values of the large and small superconducting gaps, their characteristic ratios, and the partial contributions of the two effective zones to the conductivity.
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