Pub Date : 2024-08-15DOI: 10.3103/s0027134924700516
I. N. Ivanova, O. N. Melnikova
Abstract
In the paper, the effect of natural dust deposited from the air on the evaporation rate from the water surface is experimentally investigated. Experiments were conducted for stationary liquid without wind blowing across the surface and with mild wind that does not deform the surface, at a constant rate of particle deposition. It is shown that the evaporation rate is a linear function of the difference in the saturated vapor pressure at the water surface and the partial pressure of the air mixture at the temperature and relative humidity in the laboratory at the beginning of the deposition process, when the proportion of the surface covered with dust is small. With the increase in deposition time, hydrophobic particles gather into conglomerates, reducing the proportion of the exposed surface and the evaporation rate.
{"title":"Effect of Hydrophobic Dust Particles on the Evaporation Rate from Water Surface","authors":"I. N. Ivanova, O. N. Melnikova","doi":"10.3103/s0027134924700516","DOIUrl":"https://doi.org/10.3103/s0027134924700516","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In the paper, the effect of natural dust deposited from the air on the evaporation rate from the water surface is experimentally investigated. Experiments were conducted for stationary liquid without wind blowing across the surface and with mild wind that does not deform the surface, at a constant rate of particle deposition. It is shown that the evaporation rate is a linear function of the difference in the saturated vapor pressure at the water surface and the partial pressure of the air mixture at the temperature and relative humidity in the laboratory at the beginning of the deposition process, when the proportion of the surface covered with dust is small. With the increase in deposition time, hydrophobic particles gather into conglomerates, reducing the proportion of the exposed surface and the evaporation rate.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142182055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-15DOI: 10.3103/s0027134924700462
I. V. Nikolaev, N. G. Korobeishchikov, A. V. Lapega
Abstract
The surface treatment of single-crystal germanium with an argon cluster ion beam has been investigated. The original surface of the germanium wafers was bombarded with argon cluster ions with high (105 eV/atom) and low (10 eV/atom) specific energies. Using an atomic force microscope, images were obtained and a comparison of the surface topography before and after cluster ion bombardment was conducted. The smoothing of the surface was demonstrated using the power spectral density function of roughness in the range of spatial frequencies: 1) (nu=1{-}8)(mu)m({}^{-1})—for the high-energy mode; 2) (nu=0.7{-}2.5)(mu)m({}^{-1})—for the low-energy mode.
{"title":"Effect of Cluster Ion Bombardment on the Roughly Polished Surface of Single-Crystal Germanium Wafers","authors":"I. V. Nikolaev, N. G. Korobeishchikov, A. V. Lapega","doi":"10.3103/s0027134924700462","DOIUrl":"https://doi.org/10.3103/s0027134924700462","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The surface treatment of single-crystal germanium with an argon cluster ion beam has been investigated. The original surface of the germanium wafers was bombarded with argon cluster ions with high (105 eV/atom) and low (10 eV/atom) specific energies. Using an atomic force microscope, images were obtained and a comparison of the surface topography before and after cluster ion bombardment was conducted. The smoothing of the surface was demonstrated using the power spectral density function of roughness in the range of spatial frequencies: 1) <span>(nu=1{-}8)</span>\u0000<span>(mu)</span>m<span>({}^{-1})</span>—for the high-energy mode; 2) <span>(nu=0.7{-}2.5)</span>\u0000<span>(mu)</span>m<span>({}^{-1})</span>—for the low-energy mode.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142182035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-15DOI: 10.3103/s0027134924700449
D. P. Kovalev, P. D. Kovalev
Abstract
The observation of waves (sea level oscillations) in the coastal water area of the southeastern coast of Sakhalin Island was carried out from November 2021 to May 2022 using bottom-mounted high-precision ARW 14 K devices with one second discreteness. The analysis of the obtained time series revealed the presence of anomalous waves in the range of tsunami waves in January 2022. It is shown that the waves detected on January 15, 2022 with periods of 15 min–4 h, significantly standing out above the background, are associated with volcanic tsunami waves. Spectral analysis of the time series showed that the maximum in the spectra of sea level oscillations found after the volcanic eruption is close to the period of the first mode of the shelf seiche. This indicates that incoming tsunami waves excite shelf seiches in the coastal zone and contribute to the generation of longshore and transverse seiches into Mordvinov Bay. Time series analysis made it possible to establish that the spectral density of sea level oscillations for the time interval of the beginning of the eruption of the Hunga–Tonga–Hunga–Ha’apai volcano from December 21, 2021 to January 11, 2022 significantly differs from the spectral density for the time of the Plinian volcanic eruption. An analysis of the statistical characteristics of sea level oscillations performed on two-day series in the range of periods 1 min–4 h for background waves and tsunamis showed an increase in the rms by 3.5 times for a time series containing tsunami waves. It has been established that for background time series containing tsunami waves, the coefficients of asymmetry and kurtosis differ little from ‘‘Gaussia’’ values. This indicates that the arrival of tsunami waves from distant sources does not significantly disrupt the stationarity of the wave field in the observation area.
{"title":"Tsunami Waves off the Southeastern Coast of Sakhalin Island Caused by the Eruption of the Hunga–Tonga–Hunga–Ha’apai Volcano on January 15, 2022 According to Observations by Bottom Devices of Waves","authors":"D. P. Kovalev, P. D. Kovalev","doi":"10.3103/s0027134924700449","DOIUrl":"https://doi.org/10.3103/s0027134924700449","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The observation of waves (sea level oscillations) in the coastal water area of the southeastern coast of Sakhalin Island was carried out from November 2021 to May 2022 using bottom-mounted high-precision ARW 14 K devices with one second discreteness. The analysis of the obtained time series revealed the presence of anomalous waves in the range of tsunami waves in January 2022. It is shown that the waves detected on January 15, 2022 with periods of 15 min–4 h, significantly standing out above the background, are associated with volcanic tsunami waves. Spectral analysis of the time series showed that the maximum in the spectra of sea level oscillations found after the volcanic eruption is close to the period of the first mode of the shelf seiche. This indicates that incoming tsunami waves excite shelf seiches in the coastal zone and contribute to the generation of longshore and transverse seiches into Mordvinov Bay. Time series analysis made it possible to establish that the spectral density of sea level oscillations for the time interval of the beginning of the eruption of the Hunga–Tonga–Hunga–Ha’apai volcano from December 21, 2021 to January 11, 2022 significantly differs from the spectral density for the time of the Plinian volcanic eruption. An analysis of the statistical characteristics of sea level oscillations performed on two-day series in the range of periods 1 min–4 h for background waves and tsunamis showed an increase in the rms by 3.5 times for a time series containing tsunami waves. It has been established that for background time series containing tsunami waves, the coefficients of asymmetry and kurtosis differ little from ‘‘Gaussia’’ values. This indicates that the arrival of tsunami waves from distant sources does not significantly disrupt the stationarity of the wave field in the observation area.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142182054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-15DOI: 10.3103/s0027134924700528
I. I. Mokhov
Abstract
The results of a comparative analysis of various characteristics of the temperature conditions of the planetary atmospheres in the Solar System and their dependence on orbital parameters, in particular on the length and angular frequency of the annual cycle, are presented. A root dependence on the angular frequency of the dry adiabatic lapse rate is noted. The dependence of the planetary equilibrium temperature in the form of the cubic root of the angular frequency of the annual cycle is related to Kepler’s third law. For Venus, Earth, Mars, Jupiter, and Saturn, the root dependence of the scale height and the troposphere height on the annual cycle length is manifested, and the atmospheric features of the most distant planets from the Sun—Uranus and Neptune—are noted.
{"title":"Dependence of Temperature Conditions of Planetary Atmospheres in the Solar System on the Length of the Annual Cycle","authors":"I. I. Mokhov","doi":"10.3103/s0027134924700528","DOIUrl":"https://doi.org/10.3103/s0027134924700528","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The results of a comparative analysis of various characteristics of the temperature conditions of the planetary atmospheres in the Solar System and their dependence on orbital parameters, in particular on the length and angular frequency of the annual cycle, are presented. A root dependence on the angular frequency of the dry adiabatic lapse rate is noted. The dependence of the planetary equilibrium temperature in the form of the cubic root of the angular frequency of the annual cycle is related to Kepler’s third law. For Venus, Earth, Mars, Jupiter, and Saturn, the root dependence of the scale height and the troposphere height on the annual cycle length is manifested, and the atmospheric features of the most distant planets from the Sun—Uranus and Neptune—are noted.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142182053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700322
N. N. Arsenyev, A. P. Severyukhin
Abstract
Using the examples of magic nuclei ({}^{40,48})Ca, ({}^{68,78})Ni, ({}^{132})Sn, and ({}^{208})Pb, the correlation between electric dipole polarizability and the thickness of the neutron ‘‘skin’’ has been studied. The distribution of (E1)-transition strength was calculated within the random phase approximation using the Skyrme energy density functional. Comparison with experimental data made it possible to constrain the value of nuclear symmetry energy within the range (J=30{-}37) MeV.
{"title":"Electric Dipole Polarizability of Magic Nuclei","authors":"N. N. Arsenyev, A. P. Severyukhin","doi":"10.3103/s0027134924700322","DOIUrl":"https://doi.org/10.3103/s0027134924700322","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Using the examples of magic nuclei <span>({}^{40,48})</span>Ca, <span>({}^{68,78})</span>Ni, <span>({}^{132})</span>Sn, and <span>({}^{208})</span>Pb, the correlation between electric dipole polarizability and the thickness of the neutron ‘‘skin’’ has been studied. The distribution of <span>(E1)</span>-transition strength was calculated within the random phase approximation using the Skyrme energy density functional. Comparison with experimental data made it possible to constrain the value of nuclear symmetry energy within the range <span>(J=30{-}37)</span> MeV.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700383
Mahmoud El Katib, El Mahjoub Chakir, Rajaa Sebihi, Hind Saikouk
Abstract
In positron emission tomography (PET), the scattered photons represent a major image degrading factor. The scatter fraction (SF) of PET scanners is experimentally determined following the National Electrical Manufacturers Association (NEMA) NU 2 protocol, using a polyethylene phantom with a line source inserted at 45 mm radial offset from the phantom’s center. In this work, we aim to investigate the optimal radial offset of the line source, that represents the SF of a uniformly activated phantom, for the lutetium yttrium orthosilicate (LYSO)-based uEXPLORER total body PET scanner. Additionally, we propose to study the impact of several factors (axial field-of-view (AFOV), crystal material and heterogeneities) on this optimal offset, in an effort to provide recommendations for a wide range of PET scanner configurations. We performed Monte Carlo (MC) simulations of the uEXPLORER scanner along with five phantoms of different diameters, using the Geant4 Application for Tomographic Emission (GATE) code. We performed supplemental MC simulations in which we varied the crystal material, the AFOV and we introduced bone and lung heterogeneities in the phantoms to assess their impact on the optimal offset findings. Our results demonstrated that the 45 mm offset overestimates the SF of the uniform 20 cm diameter phantom by 24.3(%). Instead, an offset of 87 mm was reproducing this SF. For the phantoms having diameters in the range of 10–50 cm, an offset of 90.7(%) of the phantom’s radius was shown to be optimal (best fit). No AFOV-related impact has been observed on this optimal offset. The influence of the heterogeneities was also small with less than 1.1(%) absolute deviation in the SF. This offset could then be used for all AFOV lengths PET scanners using LYSO crystal. The impact of the crystal material was shown to be minimal and an offset of 91.5(%) of the phantom’s radius is consequently recommended as an average for other PET scanners.
摘要 在正电子发射断层扫描（PET）中，散射光子是降低图像质量的主要因素。PET 扫描仪的散射分量（SF）是根据美国国家电气制造商协会（NEMA）NU 2 协议，使用聚乙烯假体和插入假体中心 45 毫米径向偏移的线源通过实验测定的。在这项工作中，我们的目标是研究线源的最佳径向偏移量，它代表了基于正硅酸镥钇（LYSO）的 uEXPLORER 全身 PET 扫描仪的均匀激活模型 SF。此外，我们还建议研究几个因素（轴向视场 (AFOV)、晶体材料和异质性）对最佳偏移量的影响，以便为各种 PET 扫描仪配置提供建议。我们使用 Geant4 断层扫描发射应用 (GATE) 代码对 uEXPLORER 扫描仪和五个不同直径的模型进行了蒙特卡罗 (MC) 模拟。我们进行了补充 MC 模拟，其中我们改变了晶体材料和 AFOV，并在模型中引入了骨和肺异质性，以评估它们对最佳偏移结果的影响。我们的结果表明，45 毫米的偏移量高估了均匀 20 厘米直径模型的 SF 值 24.3（%）。相反，87 毫米的偏移可以再现 SF。对于直径在 10-50 厘米范围内的模型，模型半径偏移 90.7 毫米是最佳的（最佳拟合）。在这个最佳偏移量上没有观察到与 AFOV 有关的影响。异质性的影响也很小，SF的绝对偏差小于1.1。这种偏移可用于所有使用 LYSO 晶体的 AFOV 长度 PET 扫描仪。晶体材料的影响被证明是最小的，因此建议将91.5（%）的幻影半径偏移量作为其他PET扫描仪的平均值。
{"title":"A Monte Carlo Simulation Study of the Optimal Source Offset for Scatter Fraction Estimation in PET and the Influence of the Scanner and Object Characteristics","authors":"Mahmoud El Katib, El Mahjoub Chakir, Rajaa Sebihi, Hind Saikouk","doi":"10.3103/s0027134924700383","DOIUrl":"https://doi.org/10.3103/s0027134924700383","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In positron emission tomography (PET), the scattered photons represent a major image degrading factor. The scatter fraction (SF) of PET scanners is experimentally determined following the National Electrical Manufacturers Association (NEMA) NU 2 protocol, using a polyethylene phantom with a line source inserted at 45 mm radial offset from the phantom’s center. In this work, we aim to investigate the optimal radial offset of the line source, that represents the SF of a uniformly activated phantom, for the lutetium yttrium orthosilicate (LYSO)-based uEXPLORER total body PET scanner. Additionally, we propose to study the impact of several factors (axial field-of-view (AFOV), crystal material and heterogeneities) on this optimal offset, in an effort to provide recommendations for a wide range of PET scanner configurations. We performed Monte Carlo (MC) simulations of the uEXPLORER scanner along with five phantoms of different diameters, using the Geant4 Application for Tomographic Emission (GATE) code. We performed supplemental MC simulations in which we varied the crystal material, the AFOV and we introduced bone and lung heterogeneities in the phantoms to assess their impact on the optimal offset findings. Our results demonstrated that the 45 mm offset overestimates the SF of the uniform 20 cm diameter phantom by 24.3<span>(%)</span>. Instead, an offset of 87 mm was reproducing this SF. For the phantoms having diameters in the range of 10–50 cm, an offset of 90.7<span>(%)</span> of the phantom’s radius was shown to be optimal (best fit). No AFOV-related impact has been observed on this optimal offset. The influence of the heterogeneities was also small with less than 1.1<span>(%)</span> absolute deviation in the SF. This offset could then be used for all AFOV lengths PET scanners using LYSO crystal. The impact of the crystal material was shown to be minimal and an offset of 91.5<span>(%)</span> of the phantom’s radius is consequently recommended as an average for other PET scanners.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700255
M. I. Trukhanova, P. Andreev
Abstract
There is a version of the Landau–Lifshitz equation that takes into account the Coulomb exchange interactions between atoms, expressed by the term ({sim}mathbf{s}timestrianglemathbf{s}). On the other hand, ions in magnetic materials have several valence electrons on the (d)-shell, and, therefore, the Hamiltonian of many-electron atoms with spins (S>1) should include a biquadratic exchange interaction. We propose a novel fundamental microscopic derivation of the spin density evolution equation with an explicit form of biquadratic exchange interaction using the method of many-particle quantum hydrodynamics. The equation for the spin density evolution is obtained from the many-particle Schrödinger–Pauli equation and contains the contributions of the usual Coulomb exchange interaction and the biquadratic exchange. Furthermore, the derived biquadratic exchange torque in the spin density evolution equation is proportional to the nematic tensor for the medium of atoms with spin (S=1). Our method may be very attractive for further studies of the magnetoelectric effect in multiferroics.
{"title":"A New Microscopic Representation of Spin Dynamics in Quantum Systems with Biquadratic Exchange Interactions","authors":"M. I. Trukhanova, P. Andreev","doi":"10.3103/s0027134924700255","DOIUrl":"https://doi.org/10.3103/s0027134924700255","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>There is a version of the Landau–Lifshitz equation that takes into account the Coulomb exchange interactions between atoms, expressed by the term <span>({sim}mathbf{s}timestrianglemathbf{s})</span>. On the other hand, ions in magnetic materials have several valence electrons on the <span>(d)</span>-shell, and, therefore, the Hamiltonian of many-electron atoms with spins <span>(S>1)</span> should include a biquadratic exchange interaction. We propose a novel fundamental microscopic derivation of the spin density evolution equation with an explicit form of biquadratic exchange interaction using the method of many-particle quantum hydrodynamics. The equation for the spin density evolution is obtained from the many-particle Schrödinger–Pauli equation and contains the contributions of the usual Coulomb exchange interaction and the biquadratic exchange. Furthermore, the derived biquadratic exchange torque in the spin density evolution equation is proportional to the nematic tensor for the medium of atoms with spin <span>(S=1)</span>. Our method may be very attractive for further studies of the magnetoelectric effect in multiferroics.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700346
A. P. Abdullaev, D. M. Gafarova
Abstract
Based on the band structure of TlGaTe({}_{2}) compound, the extrema of the valence and conduction bands were determined and the tensor of the components of the inverse effective mass of electrons and holes was calculated.
{"title":"Calculation of the Effective Mass of Electrons and Holes of the TlGaTe $${}_{mathbf{2}}$$ Compound","authors":"A. P. Abdullaev, D. M. Gafarova","doi":"10.3103/s0027134924700346","DOIUrl":"https://doi.org/10.3103/s0027134924700346","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Based on the band structure of TlGaTe<span>({}_{2})</span> compound, the extrema of the valence and conduction bands were determined and the tensor of the components of the inverse effective mass of electrons and holes was calculated.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700334
Yu. A. Kupryakov, K. V. Bychkov, O. M. Belova, V. A. Maliutin, A. B. Gorshkov
Abstract
The paper presents the results of the analysis of the sloar flare SOL2012-04-27 emission in hydrogen, helium, and calcium spectral lines observed on the horizontal solar facility HSFA-2 of the Ondřejov Observatory (Astronomical Institute of the Czech Academy of Sciences). After processing the spectra, the integrated emission fluxes in the lines were determined. The data collected are treated using the approach of rapid energy release inside the chromosphere, accompanied by gas evaporation. Within the framework of the heated gas model, a theoretical calculation of the plasma parameters was performed, taking into account the physical conditions in the chromosphere, including spectral line self-absorption. Comparison across six lines allowed, with a high degree of validity, the reconstruction of the temperature (T), density, and spatial structure of the emitting gas. The best agreement of theory with observations is obtained in the model of the spread of inhomogeneous clouds, each of which has hot ((Tapprox 18,000{-}19,500) K) and less heated ((Tapprox 8000{-}9000) K) regions. On average, one cloud contributes about ten percent to the total emission flux.
{"title":"Simulation of the April 27, 2012 Flare Emission in the Spectral Lines of Hydrogen, Helium, and Calcium","authors":"Yu. A. Kupryakov, K. V. Bychkov, O. M. Belova, V. A. Maliutin, A. B. Gorshkov","doi":"10.3103/s0027134924700334","DOIUrl":"https://doi.org/10.3103/s0027134924700334","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The paper presents the results of the analysis of the sloar flare SOL2012-04-27 emission in hydrogen, helium, and calcium spectral lines observed on the horizontal solar facility HSFA-2 of the Ondřejov Observatory (Astronomical Institute of the Czech Academy of Sciences). After processing the spectra, the integrated emission fluxes in the lines were determined. The data collected are treated using the approach of rapid energy release inside the chromosphere, accompanied by gas evaporation. Within the framework of the heated gas model, a theoretical calculation of the plasma parameters was performed, taking into account the physical conditions in the chromosphere, including spectral line self-absorption. Comparison across six lines allowed, with a high degree of validity, the reconstruction of the temperature <span>(T)</span>, density, and spatial structure of the emitting gas. The best agreement of theory with observations is obtained in the model of the spread of inhomogeneous clouds, each of which has hot (<span>(Tapprox 18,000{-}19,500)</span> K) and less heated (<span>(Tapprox 8000{-}9000)</span> K) regions. On average, one cloud contributes about ten percent to the total emission flux.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700188
I. A. Artyukov, A. V. Vinogradov, V. I. Shevdunov
Abstract
The paper, like the seminar where it was presented, is dedicated to the memory of the outstanding physicist and nuclear scientist, Professor of Moscow State University B.S. Ishkhanov, more precisely, to his contribution to the research and development of LEXG—laser–electron X-ray generators. The relevance and prospects of this direction are associated with the ‘‘gap’’ between two existing types of X-ray generators: on the one hand, X-ray tubes, and on the other, electron accelerators, storage rings, and free electron lasers. This involves a vast difference in beam characteristics, cost, scale, energy consumption, etc. The history of LEXG, modern projects abroad, as well as the Lomonosov Moscow State University–Jilin University project, carried out under the supervision of B.S. Ishkhanov, are briefly presented. From the point of view of their applications, LEXG designs can be divided into two types and, accordingly, devices of different scales. In the first case, it is the application area of common X-ray tubes, and in the second, it is radiation medicine, nuclear technologies, and nuclear physics research. International conferences on LEXG have been held since 2008. Their list is provided in the Appendix to the article.
摘 要 本文和它发表的研讨会一样，都是为了纪念杰出的物理学家和核科学家、莫斯科国立大学教授 B.S. Ishkhanov，更确切地说，是为了纪念他对研究和开发 LEXG-激光电子 X 射线发生器所做的贡献。这一方向的相关性和前景与现有两类 X 射线发生器之间的 "差距 "有关：一方面是 X 射线管，另一方面是电子加速器、存储环和自由电子激光器。这涉及到光束特性、成本、规模、能耗等方面的巨大差异。本文简要介绍了 LEXG 的历史、国外的现代项目以及在 B.S. Ishkhanov 指导下实施的莫斯科国立大学-吉林大学罗蒙诺索夫项目。从应用的角度来看，LEXG 设计可分为两种类型，并相应地分为不同规模的装置。第一种是普通 X 射线管的应用领域，第二种是放射医学、核技术和核物理研究领域。自 2008 年以来，有关 LEXG 的国际会议不断召开。会议列表见本文附录。
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