Geomagnetism and Aeronomy最新文献

{"title":"Using Classification Methods in Forecasting the Level of Geomagnetic Field Disturbance Based on the Kp-Index","authors":"I. M. Gadzhiev,&nbsp;O. G. Barinov,&nbsp;I. N. Myagkova,&nbsp;S. A. Dolenko","doi":"10.1134/S0016793224600140","DOIUrl":"10.1134/S0016793224600140","url":null,"abstract":"<p>The paper explores the possibilities of using data classification methods when forecasting time series of the geomagnetic <i>Kp</i>-index by machine learning methods. To classify categories of the <i>Kp</i>-index based on the degree of disturbance, linear and logistic regression, random forest, gradient boosting on top of decision trees, and artificial neural networks of various architectures are used. The results of these methods are compared with a trivial inertial forecast (the statistical indicators of which for problems of this type are always high) at horizons from 3 h to 1 day in 3-h increments. The problem of choosing a cross-validation scheme for selecting the model hyperparameters, ways to overcome the imbalance of categories, the relative importance of input features, as well as the dependence of the results on the test sample (beginning of the 25th solar activity cycle) on inclusion in the training sample of data from the 23rd and 24th cycles or only the 24th cycles are studied. Based on the results, conclusions are drawn about the preferred methods for classifying values of the <i>Kp</i>-index based on the level of geomagnetic disturbance. Ways for further research and possible improvement of the classification quality are outlined, including for determining the characteristic hidden states of Earth’s magnetosphere as a dynamic system in order to improve the quality of forecasting geomagnetic indices.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518510","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}

{"title":"Ionospheric Features of Polar Cusp Dayside Precipitation for a Northern IMF","authors":"V. G. Vorobjev,&nbsp;O. I. Yagodkina,&nbsp;E. E. Antonova","doi":"10.1134/S0016793224600103","DOIUrl":"10.1134/S0016793224600103","url":null,"abstract":"<p>Geophysical processes in the region of the dayside polar cusp on December 22, 2003, were studied for a northern orientation of the interplanetary magnetic field (IMF) and a relatively high-velocity, low-density solar wind, using ground-based optical observations in Svalbard and DMSP F16 satellite data. Comparison of satellite and ground-based observations shows that soft electron precipitation in the cusp region determines the auroral glow in the 630.0 nm (OI) emission. The peculiarity of the considered event is observation of a bright rayed arc of the aurora rimming the dayside cusp from its polar edge. The results of observations by the low-flying DMSP F16 satellite as it intersected the rayed arc were analyzed. Explanations for the observed phenomena are proposed, based on analysis of changes in the spectra of precipitating electrons and formation of a field-aligned electron beam by the field-aligned electric field.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141503756","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}

{"title":"Lithospheric Magnetic Anomalies of the Polar Arctic According to CHAMP Satellite Data","authors":"D. Yu. Abramova,&nbsp;L. M. Abramova","doi":"10.1134/S0016793224600036","DOIUrl":"10.1134/S0016793224600036","url":null,"abstract":"<p>The study of the deep structure and tectonics of the Arctic region is relevant not only for solving fundamental problems of modern geodynamics, but also for developing natural resources in the circumpolar regions; it is also of interest from the geopolitical view when determining the boundaries of the marginal seas shelves. To analyze the anomalous magnetic field in the Polar Arctic region, experimental CHAMP satellite data were used, obtained at the last stage of its operation, when the orbit altitude decreased to 280–260 km, which made it possible to obtain geomagnetic parameters with higher spatial resolution. For several sectors of the Polar Arctic, maps of the lithospheric magnetic anomalies field distribution for various scales and degrees of averaging over this area were constructed. The anomalies parameters were analyzed and an explanation was proposed for the geological and physical nature of the anomalies, which are images of the most significant geological–tectonic structures of the North Atlantic Igneous Province and complex of Central Arctic underwater rises. The article discusses the relationships between the discovered features of the lithospheric anomalous magnetic field distribution, and the known geological structures of Amerasia and Eurasia, and tectonic processes that occurred here in the past and still proceed now. The results obtained are of interest for further comprehensive geological and geophysical studies and construction of substantiated models of the Arctic region lithosphere evolution.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141531252","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}

{"title":"Vector Magnetic Field Reconstruction from Single-Component Data Using Evolutionary Algorithm","authors":"R. A. Rytov,&nbsp;N. A. Usov,&nbsp;V. G. Petrov","doi":"10.1134/S0016793224600164","DOIUrl":"10.1134/S0016793224600164","url":null,"abstract":"<p>A simple evolutionary algorithm is proposed to reconstruct a vector anomalous magnetic field from measurement data of one of its components. The algorithm selects the positions and magnetic moments of an assembly of point magnetic dipoles, the total magnetic field of which approximates with the required accuracy the data of single-component magnetic measurements at a known height above the earth’s surface. The distribution of sources obtained in this manner enables the reconstruction of all three components of the magnetic field. In this study, an evolutionary algorithm was utilized to solve the problem of reconstructing the magnetic field components <span>({{H}_{x}})</span> and <span>({{H}_{y}})</span> from the measured <span>({{H}_{z}})</span> vertical component data. Additionally, an iterative procedure was proposed for calculating the <span>({{H}_{x}})</span>, <span>({{H}_{y}})</span> and <span>({{H}_{z}})</span> components of the magnetic field from known data for the anomalous component of the geomagnetic field.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141531251","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}

{"title":"Forbush Effects and Geomagnetic Storms","authors":"A. V. Belov,&nbsp;E. A. Belova,&nbsp;N. S. Shlyk,&nbsp;M. A. Abunina,&nbsp;A. A. Abunin,&nbsp;S. M. Belov","doi":"10.1134/S0016793224600097","DOIUrl":"10.1134/S0016793224600097","url":null,"abstract":"<p>Forbush effects in galactic cosmic rays (according to the neutron monitor network data) and accompanying geomagnetic disturbances over a long period from 1957 to 2022 have been identified and studied. Statistical relationships between various parameters of cosmic ray flux variations and geomagnetic activity indices are analyzed. It has been established that the magnitude of Forbush effects depends nonlinearly on the class of geomagnetic storm. A moderate correlation (up to 0.67) was found between the extreme values of various geomagnetic activity indices (<i>Ap</i>, <i>Kp</i>, <i>Dst</i>) and cosmic ray characteristics. It is shown that the extreme values of cosmic ray and geomagnetic activity parameters are not always detected simultaneously: it depends on the sign of the <i>Bz</i>-component of the interplanetary magnetic field in a specific event.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141503755","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}

{"title":"Study of Sudden Magnetic Storm Commencement from Observations with Second Time Resolution","authors":"Yu. S. Zagainova,&nbsp;S. V. Gromov,&nbsp;L. I. Gromova,&nbsp;V. G. Fainshtein","doi":"10.1134/S0016793224600152","DOIUrl":"10.1134/S0016793224600152","url":null,"abstract":"<p>The article presents the results of a studying detection of the sudden commencement (SC) and main impulse (MI) of a magnetic storm as a function of the geographic coordinates of magnetic observatories and Universal Time, using modern data with second time resolution. The analysis was carried out for two events in which an interplanetary shock wave impacting the magnetosphere was associated with interplanetary coronal mass ejections (CMEs) with sources in different hemispheres of the Sun. The authors propose an approach to determine the time points of SC and MI detection. It is concluded that the SC and MI detection times may differ by several seconds to more than a minute at magnetic observatories located at different geographic latitudes and longitudes. For the studied events, the graphs of SC and MI detection as functions of the geographic coordinates of magnetic observatories and Universal Time revealed trends according to which, on average, the higher station the latitude, the later SC and MI are detected at the station.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141503757","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}

{"title":"Spatial Structure of Plasma Density Disturbances in the Topside Ionosphere Caused by High-Power HF Heating of the F2 Layer","authors":"V. L. Frolov,&nbsp;E. S. Andreeva,&nbsp;A. M. Padokhin","doi":"10.1134/S0016793224600127","DOIUrl":"10.1134/S0016793224600127","url":null,"abstract":"<p>The study analyzes the results of low-orbital satellite radio tomography measurements of the spatial structure of artificial electron-density variations Earth’s topside ionosphere excited during modification of the <i>F</i>2 layer of the mid-latitude ionosphere by high-power <i>O-</i>polarized HF radio waves emitted by the SURA heating facility. The article considers the characteristics of the cavity with a reduced plasma density that forms near the reflection height of a high-power HF radio wave, ducts with increased plasma density that form in the topside ionosphere due to displacement of plasma from the heated region along the geomagnetic field, and various wave disturbances induced at ionospheric heights. In addition, the properties of detected plasma density disturbances of a special nature in the vertical column above the central part of the disturbed region of the ionosphere are also investigated. The sizes of the studied irregularities are from several tens to several hundreds of kilometers, and the area of their existence goes far beyond the region of resonance interaction of a high-power <i>O-</i>polarized radio wave with ionospheric plasma near its reflection height, where the most intense artificial ionospheric turbulence is excited.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141503758","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}

{"title":"Compliance of AE and Apo Indices Variations during 23−24 Solar Cycles","authors":"T. L. Gulyaeva","doi":"10.1134/S0016793224600115","DOIUrl":"10.1134/S0016793224600115","url":null,"abstract":"<p>The auroral electrojet index <i>AE</i> is often used in forecasting models as a driver of the disturbance propagation in the geosphere from the pole to middle and low latitudes. However, these data are not available digitally since January 2020. Instead of the <i>AE</i>-index, we suggest using the recently introduced 1 h <i>Apo</i>-index, given the close proximity of magnetometer networks for these indices at high latitudes and the availability of the <i>Apo</i>-index in real time. To this end their correlation is analyzed during 276 intense storms for 1995–2017. Storm profiles are constructed by method of superposed epochs with zero epoch time <i>t</i>₀ = 0 taken at the threshold value of <i>AE</i> ≥ 1000 nT. A comparison is made of the storm profiles of <i>AE</i>(<i>t</i>), <i>Apo</i>(<i>t</i>), the interplanetary electric field <i>E</i>(<i>t</i>) and the solar wind speed <i>Vsw</i>(<i>t</i>) within 72 h: 24 h before the storm peak <i>t</i>₀, and 48 h afterward. A good agreement is obtained between the sets of <i>AE</i>(<i>t</i>) and <i>Apo</i>(<i>t</i>) with a correlation coefficient of 0.70. Comparison with the interplanetary parameters testifies on the correlation of <i>AE</i>(<i>t</i>) and <i>Apo</i>(<i>t</i>) with the electric field <i>E</i>(<i>t</i>) but missing their linkage with the solar wind speed <i>Vsw</i>(<i>t</i>). A two-parametric formula is derived for dependence of the auroral electrojet index <i>AE</i>(<i>t</i>) on the interplanetary electric field <i>E</i>(<i>t</i>) and the geomagnetic <i>Apo</i>(<i>t</i>) index for the geomagnetic storm forecasting. In the absence of <i>E</i>(<i>t</i>) data, formulae for the dependence of <i>AE</i>(<i>t</i>) on <i>Apo</i>(<i>t</i>) is introduced for implementation in real time and the inverse dependence of <i>Apo</i>(<i>t</i>) on <i>AE</i>(<i>t</i>) for reconstruction of the 1 h <i>Apo</i>-index before 1995. Validation of the proposed models with data for 5 intense storms in 2018 has shown a close resemblance of the model with observation data of the <i>AE</i>-index with a high coefficient of determination <i>R</i> ² ranging from 0.62 to 0.81.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141518509","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}

{"title":"Determination of the Velocity of Ionospheric Disturbances from the Dynamics of Additional U-Shaped Traces on Ionograms","authors":"O. A. Laryunin,&nbsp;V. I. Kurkin,&nbsp;A. A. Rybkina,&nbsp;A. V. Podlesnyi","doi":"10.1134/S0016793223601084","DOIUrl":"10.1134/S0016793223601084","url":null,"abstract":"<p>One of the approaches to solving the inverse problem of determining the parameters of ionospheric disturbances is the multiple solution of the two-point problem with the subsequent comparison of the simulation results with experimental data (ionograms). However, this approach is usually associated with significant calculation time costs, which makes it impossible to process large arrays of sounding data. The method described in this article makes it possible to quickly determine the horizontal velocity of the ionospheric disturbance by descent rate of an additional U-shaped trace moving to lower virtual heights on the vertical sounding ionograms: in order to calculate the velocity, it is proposed to use the results of the ray tracing obtained for the reference background profiles with disturbances superimposed on them.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140803824","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}

{"title":"Evolution of Characteristics of Vertical Electric Current and Magnetic Field in Active Regions of the Sun and Their Relation to Powerful Flares","authors":"A. B. Nechaeva,&nbsp;I. V. Zimovets,&nbsp;V. S. Zubik,&nbsp;I. N. Sharykin","doi":"10.1134/S0016793223601060","DOIUrl":"10.1134/S0016793223601060","url":null,"abstract":"<p>The study of evolution of magnetic field and electric currents in active regions of the Sun over a long-time interval is of interest for understanding the processes of energy accumulation and release in them, leading to various phenomena that affect space weather. In this study, based on the photospheric vector magnetograms of the helioseismic and magnetic imager instrument aboard the Solar Dynamics Observatory, the authors analyzed the evolution of a number of characteristics of the magnetic field and vertical electric current in three active regions, 11 158, 11 675, and 12 673, that produced M and X class flares, during the time from their origin in the eastern hemisphere, during passage through the solar disk, and until their disappearance near the western limb with a step of 2 h. The characteristics considered included: the power-law exponent of the probability density function of the absolute value of the vertical electric current density, the maximum absolute value of the vertical current density, the signed and unsigned total vertical currents and the unsigned total vertical and horizontal magnetic fluxes, the energy of the nonlinear force-free and potential magnetic fields, the free magnetic energy, and the number of islands with strong vertical current. Some regularities in the behavior of the characteristics considered are found, in particular, regarding the occurrence of solar flares. The correlation coefficients between pairs of these characteristics are calculated. Additionally, M. Aschwanden’s approach is shown to be promising for predicting the maximum X-ray class of a flare by calculating the energy of the potential magnetic field in active regions. The results can be used to predict powerful solar flares.</p>","PeriodicalId":55597,"journal":{"name":"Geomagnetism and Aeronomy","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140806647","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}