Radiophysics and Quantum Electronics最新文献_第6页

Acoustic Turbulence: From the Zakharov–Sagdeev Spectra to the Kadomtsev–Petviashvili Spectrum 声湍流：从Zakharov-Sagdeev谱到Kadomtsev-Petviashvili谱

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-04-25 DOI: 10.1007/s11141-026-10465-z

E. A. Kochurin, E. A. Kuznetsov

{"title":"Acoustic Turbulence: From the Zakharov–Sagdeev Spectra to the Kadomtsev–Petviashvili Spectrum","authors":"E. A. Kochurin, E. A. Kuznetsov","doi":"10.1007/s11141-026-10465-z","DOIUrl":"10.1007/s11141-026-10465-z","url":null,"abstract":"We present a brief review of theoretical and numerical works on three-dimensional acoustic turbulence both in a weakly nonlinear regime, when the amplitudes of sound waves are small, and in the case of strong nonlinearity. This review is based on the classical studies on weak acoustic turbulence by V. E. Zakharov and R. Z. Sagdeev [1, 2], on the one hand, and by B. B.Kadomtsev and V. I. Petviashvili on the other hand [3]. Until recently, there have been no convincing numerical experiments confirming one or the other point of view. In works [4, 5] by the authors of this review, strong arguments were found based on direct numerical simulation in favor of both theories. It is shown that the spectrum of weak Zakharov–Sagdeev turbulence ∝ k-3/2 is realized not only at low positive dispersion of sound waves, but also in the case of complete absence of dispersion. The calculated turbulence spectra in the weakly nonlinear regime have anisotropic distribution: in the region of small k, narrow cones (jets), broadening in the Fourier space, are formed. In the case of weak dispersion, the jets are smoothed out, and the turbulence spectrum tends to be isotropic in the region of short wavelengths. In the absence of dispersion, the turbulence spectrum is a discrete set of jets subject to diffraction divergence. It is found that for each individual jet, nonlinear effects are much weaker than diffraction ones, which prevents the formation of shock waves. Thus, the spectra of weak Zakharov–Sagdeev turbulence are realized due to the smallness of nonlinear effects compared with dispersion or diffraction. As the pumping level increases in the dispersionless regime, when nonlinear effects start to dominate, shock waves, namely, discontinuities propagating in space, are formed. As a result, acoustic turbulence passes into a strongly nonlinear state in the form of an ensemble of random shock waves described by the Kadomtsev–Petviashvili spectrum decaying by the law ∝ k-2.","PeriodicalId":748,"journal":{"name":"Radiophysics and Quantum Electronics","volume":"68 5-6","pages":"374 - 390"},"PeriodicalIF":0.7,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147865779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of Functional Brain Networks Recovered from Functional Magnetic Resonance Imaging Data 从功能磁共振成像数据中恢复的功能性脑网络分析

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-04-25 DOI: 10.1007/s11141-026-10468-w

L. A. Mayorova, S. A. Kurkin, V. S. Khorev, A. N. Kuzovlev, A. A. Yakovlev, A. V. Grechko, A. E. Hramov

{"title":"Analysis of Functional Brain Networks Recovered from Functional Magnetic Resonance Imaging Data","authors":"L. A. Mayorova, S. A. Kurkin, V. S. Khorev, A. N. Kuzovlev, A. A. Yakovlev, A. V. Grechko, A. E. Hramov","doi":"10.1007/s11141-026-10468-w","DOIUrl":"10.1007/s11141-026-10468-w","url":null,"abstract":"This review considers state-of-the-art methods for analyzing functional brain networks recovered from functional magnetic resonance imaging (fMRI) data. The focus is on the application of mathematical and computational approaches, including complex network theory and machine learning methods, to study topological properties and differences of functional connectivity in the brain. Various functional network recovery methods such as correlation, information, regression, and pattern-based approaches and their application to the diagnosis of neurological and psychiatric disorders, including Alzheimer’s disease, schizophrenia, and depression, are discussed. Special attention is paid to the problem of intersubject variability of data and methods to overcome it, including the concept of consensus networks. Prospects for using machine learning, in particular graph neural networks, to classify functional networks and identify disease biomarkers, are considered. Finally, future research directions, including the study of higher-order interactions in functional brain networks, which may lead to the development of new diagnostic and therapeutic strategies, are discussed.","PeriodicalId":748,"journal":{"name":"Radiophysics and Quantum Electronics","volume":"68 5-6","pages":"416 - 431"},"PeriodicalIF":0.7,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147865780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dynamics of Nonlinear Wave Systems Admitting Singularity Formation 允许奇点形成的非线性波动系统动力学

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-04-25 DOI: 10.1007/s11141-026-10470-2

V. A. Glazatov, V. Zh. Sakbaev

引用次数: 0

Simultaneous Observations of Quasi-Periodic VLF Emissions by Spacecraft and on the Ground and Localization of Their Generation Region 宇宙飞船和地面准周期VLF发射的同时观测及其产生区域的定位

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-03-23 DOI: 10.1007/s11141-026-10456-0

A. G. Demekhov, E. E. Titova, A. A. Lyubchich, D. L. Pasmanik, J. Manninen, A. V. Larchenko

{"title":"Simultaneous Observations of Quasi-Periodic VLF Emissions by Spacecraft and on the Ground and Localization of Their Generation Region","authors":"A. G. Demekhov, E. E. Titova, A. A. Lyubchich, D. L. Pasmanik, J. Manninen, A. V. Larchenko","doi":"10.1007/s11141-026-10456-0","DOIUrl":"10.1007/s11141-026-10456-0","url":null,"abstract":"We present the results of studies of simultaneous ground-based and spacecraft observations of quasiperiodic VLF emissions. About 20 events were selected in which a one-to-one correspondence between the elements of quasi-periodic emissions onboard the Van Allen Probes spacecraft and at the Kannuslehto ground-based observatory (Finland, 67.74°N, 26.27°E; McIlwain parameter L ≈ 5.5) was observed. This correspondence occurred over a wide range of latitudes (~ 20°) and longitudes (~ 90°) at distances of up to 3000 km between the geomagnetic projection of the spacecraft trajectory to the Earth and the ground-based station. By using multicomponent wave field measurements onboard Van Allen Probes spacecraft, we found the sections of their orbits at which the VLF waves propagated almost along the geomagnetic field and the energy flux (Poynting vector) was directed away from the geomagnetic equator. Using the data on the energetic electron distribution function obtained by the same spacecraft we calculated the growth rate of the cyclotron instability of whistler-mode waves in the magnetosphere. Comparison of the results of these calculations with the results of multicomponent VLF wave measurements allowed us to find probable generation regions of quasi-periodic emissions. It is shown that these regions are clustered in the L-shell interval from 4 to 5.5, and their characteristic radial size is ΔL ≈ 0.1–0.5, which is much smaller than the size of the quasi-periodic emission observation region (ΔL ≈ 1–3).","PeriodicalId":748,"journal":{"name":"Radiophysics and Quantum Electronics","volume":"68 4","pages":"249 - 269"},"PeriodicalIF":0.7,"publicationDate":"2026-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147636902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Scientific Works by M. I. Rabinovich and Modern Theory of Oscillations and Waves 拉宾诺维奇的科学著作和现代振荡与波动理论

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-03-21 DOI: 10.1007/s11141-026-10462-2

I. S. Aranson, A. I. Malekhanov, V. I. Nekorkin, A. S. Pikovsky, L. Sh. Tsimring, A. L. Fabrikant

引用次数: 0

Estimation of the Initial Approximation for the Radio Source Positioning Problem Based on Limited Satellite Constellations 基于有限卫星星座的射电源定位问题的初始逼近估计

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-03-21 DOI: 10.1007/s11141-026-10461-3

I. V. Grin, O. A. Morozov, M. A. Nalchajyan

引用次数: 0

Reflection of a Gaussian Beam from an Arbitrary Number of Plane-Parallel Dielectric Plates 高斯光束在任意数目平行介质板上的反射

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-03-21 DOI: 10.1007/s11141-026-10460-4

A. V. Ryabov, A. V. Palitsin

引用次数: 0

On Determination of the Atmospheric Optical Thickness from Absolute Measurements of Sky Brightness Temperature in the Millimeter Wavelength Range 利用毫米波段天空亮度温度的绝对测量确定大气光学厚度

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-03-20 DOI: 10.1007/s11141-026-10459-x

I. I. Zinchenko, E. A. Kopylov

引用次数: 0

Critical Currents in Coronal Magnetic Loops and Their Possible Manifestation During Flare Processes 日冕磁环中的临界电流及其在耀斑过程中的可能表现

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-03-20 DOI: 10.1007/s11141-026-10455-1

V. V. Zaitsev, T. V. Simonova

引用次数: 0

Peculiarities of the HF Signal Mode Structure on Mid-Latitude Radio Paths During Geomagnetic Storms in November–December 2023 2023年11 - 12月地磁暴中纬度无线电路径高频信号模式结构特征

IF 0.7 4区地球科学

Radiophysics and Quantum Electronics Pub Date : 2026-03-20 DOI: 10.1007/s11141-026-10457-z

S. N. Ponomarchuk, N. A. Zolotukhina, V. I. Kurkin

{"title":"Peculiarities of the HF Signal Mode Structure on Mid-Latitude Radio Paths During Geomagnetic Storms in November–December 2023","authors":"S. N. Ponomarchuk, N. A. Zolotukhina, V. I. Kurkin","doi":"10.1007/s11141-026-10457-z","DOIUrl":"10.1007/s11141-026-10457-z","url":null,"abstract":"Geomagnetic storms are followed by ionospheric disturbances of various kinds (ionospheric storms) that change the conditions of HF propagation. Radio wave propagation is most significantly affected by the spatial location of large-scale structures such as the main ionospheric trough and the zone of diffuse electron precipitation. During magnetic storms, they shift to lower latitudes, causing strong variations in the maximum observed frequencies (MOFs) of radio wave propagation on mid-latitude paths, deviation of signal propagation trajectories from the great-circle arc, and the occurrence of anomalous diffuse signals with delays exceeding those of the regular propagation modes, as well as the absence of radio wave transmission. From the analysis of oblique ionospheric sounding with a continuous chirp signal on the Magadan–Irkutsk and Norilsk–Irkutsk paths, we studied the peculiarities of the HF signal mode structure during strong and moderate magnetic storms in November–December 2023. Relation between MOF variations and positions of the main ionospheric trough and the equatorial boundary of the diffuse electron precipitation zone relative to the propagation path was revealed.","PeriodicalId":748,"journal":{"name":"Radiophysics and Quantum Electronics","volume":"68 4","pages":"270 - 285"},"PeriodicalIF":0.7,"publicationDate":"2026-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147636903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0