Kinematics and Physics of Celestial Bodies最新文献

{"title":"Resonance Electromagnetic Effect of the Kamchatka Meteoroid","authors":"Y. Luo,&nbsp;L. F. Chernogor","doi":"10.3103/S0884591323010051","DOIUrl":"10.3103/S0884591323010051","url":null,"abstract":"<p>A large meteoroid entered the terrestrial atmosphere and exploded at an altitude of 26 km between the Kamchatka Peninsula and Alaska (geographic coordinates 56.9° N, 172.4° E) over the Bering Sea at 23:48:20 UT on December 18, 2018. The meteoroid has been named the Kamchatka (or Bering Sea) meteoroid. Its basic parameters are as follows: calculated total impact energy 173 kt of TNT, total optical radiated energy 1.3 × 10¹⁴ J, mass 1.41 kt, speed 32 km/s, size 9.4 m, and the trajectory directed at an angle of 68.6° with respect to the horizon. The entry of the Kamchatka meteoroid into the atmosphere was accompanied by the generation of a transient resonance electromagnetic signal in the 25–35 mHz band observable in the vicinity of the meteoroid explosion and in the magnetically conjugate region. Oscillations with amplitudes of 0.2–0.8 nT were observed over a 7-min interval. This study is aimed at analyzing the observations of the resonance electromagnetic effect from the Kamchatka meteoroid and discussing a mechanism for this effect. The resonance effect in the Earth’s magnetic field is analyzed using data with a time resolution of 1 s and an amplitude resolution of 1 nT from the database collected by the Intermagnet magnetometer network of magnetic observatories. The distance between the site of the meteoroid explosion and the magnetic observatories ranges from 1000 to 5000 km in the Northern Hemisphere and from 9010 to 12 425 km in the Southern Hemisphere. It is established that the only feasible mechanism is associated with the magnetic field displacement in the magnetosphere by the explosive impact of the celestial body, whereas only a negligibly small part of the meteoroid’s energy is spent on the generation of magnetic field perturbations. The meteoroid’s energy losses are similar to the losses in the reactive components of the radio frequency circuits, i.e., they return into the system. The oscillations cease after the meteoroid flies by, and the system returns into the initial state. The main results are summarized as follows. The resonance electromagnetic oscillations arose at 13 and 3 min prior to the Kamchatka meteoroid explosion. The duration of each observed perturbation is close to 7 min. The parameters of the quasi-periodic perturbations are similar to the parameters of magnetic Pc3 pulsations; however, they occured in the <i>Y</i> component of the magnetic field rather than in the <i>X</i> component of the magnetic field. Their observed periods are in the range of 33–36 s, and the amplitudes are in the range of 0.4–0.9 nT. Similar resonance oscillations were also recorded in the magnetically conjugate region. A mechanism for generating the resonance oscillations is proposed. The essence of the mechanism is that the meteoroid explosively impacts the magnetosphere and deforms the magnetic field lines that begin to oscillate at their eigenfrequencies. Depending on the McIlwain <i>L</i>-shell, the calculated period of osc","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 1","pages":"1 - 9"},"PeriodicalIF":0.5,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4801920","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}

{"title":"Photometric Variability of BL Lacertae and 1ES 1426+428 Blazars in the Optical and Gamma Ranges","authors":"І. O. Izviekova,&nbsp;V. A. Ponomarenko,&nbsp;N. G. Pulatova,&nbsp;V. V. Vasylenko,&nbsp;A. O. Simon","doi":"10.3103/S0884591322060034","DOIUrl":"10.3103/S0884591322060034","url":null,"abstract":"<div><p>The results of photometric observations of two bright blazars of the northern hemisphere, namely, BL Lacertae and 1ES 1426+428, during 2018–2020 through <i>BVRI</i> filters of the Johnson/Bessel system are given. The observations were performed with the two telescopes: AZT-8 of observation station Lisnyky of the Astronomical Observatory of the Taras Shevchenko National University of Kyiv (Kyiv oblast, Ukraine) and Zeiss-600 of high-altitude observatory Peak Terskol of the International Center for Astronomical, Medical, and Ecological Research (IC AMER) of the National Academy of Sciences of Ukraine. In total, more than sixty nights of observations were recorded and processed. The main goals have been in performing a cross-matching analysis of blazar light curves in <i>BVRI</i> bands to detect the short-term variability (STV) and long-term variability (LTV) and to investigate the chromaticity of color parameters. For both objects, fluctuations of brightness up to 1^<i>m</i> in 2018–2020 were recorded in the <i>BVRI</i> bands of the Johnson/Bessel system with a total error of 0.03^<i>m</i>–0.1^<i>m</i>. The intraday variability (IDV) was revealed for BL Lacertae November 17/November 18, 2018. During the calculations of the color indices, the trend of bluish color with an increase in the brightness (bluer-when-brighter, BWB) was found. For BL Lacertae, the LTV was reliably detected by using different pairs of filters. Also, the BWB trend with an average correlation (over 0.5) was recorded for 1ES 1426+428. The presence of such fluctuations in the color of blazars was due to the synchrotron radiation of the jet. The revealed partial correlation of variations in brightness with low time resolution (more than a week) between the photometric optical observations and the data of the Fermi gamma-ray telescope in 2018–2020 require additional research.</p></div>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 6","pages":"328 - 339"},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4650241","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}

{"title":"Properties of Acoustic-Gravity Waves at the Boundary of Two Isothermal Media","authors":"A. K. Fedorenko,&nbsp;E. I. Kryuchkov,&nbsp;O. K. Cheremnykh,&nbsp;S. V. Melnychuk,&nbsp;I. T. Zhuk","doi":"10.3103/S0884591322060022","DOIUrl":"10.3103/S0884591322060022","url":null,"abstract":"<div><p>The properties of evanescent acoustic-gravity waves that can propagate along the interface between two isothermal half-spaces with different temperatures are studied. In such a model, the condition of a simultaneous decrease in the wave energy density below and above the interface between the media is not satisfied for the known surface <i>f</i> mode. This study shows that it is possible to implement evanescent waves in the form of combinations of <i>f</i> modes and pseudo-modes (<i>f</i>_<i>p</i> modes) for both half-spaces at the interface between two isothermal media. The cross-linking of solutions at the interface depends on the wave spectral parameters and the magnitude of the temperature jump. At the interface, the wave properties change with an increase in the wavelength and their dispersion and polarization acquire features characteristic of acoustic-type waves. These differences are manifested not only in the dispersion dependence of the waves but also in the change in their amplitudes with height, polarization, and velocity divergence at the interface between the media. It is also found for large temperature differences between the lower and upper half-spaces that there is a spectral region in which the solutions satisfying the boundary condition cannot simultaneously decrease in energy below and above the interface. In this region of the spectrum, the <i>f</i>_<i>p</i> modes with a decreasing energy in the upper half-space and the <i>f</i> modes with an increasing energy in the lower half-space are joined at the interface. The considered waves at the interface between two media can be observed in the stratified atmosphere at altitudes with a sharp temperature change, for example, in the lower part of the Earth’s thermosphere or in the chromosphere–corona transition region on the Sun.</p></div>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 6","pages":"340 - 350"},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4333216","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}

{"title":"The Asymptotic Directions of Approach and the Magnetic Rigidity Cutoff of Cosmic Ray Particles for Airports at Different Latitudes and Longitudes","authors":"Witold Wozniak,&nbsp;Krzysztof Iskra,&nbsp;Marek Siluszyk","doi":"10.3103/S088459132206006X","DOIUrl":"10.3103/S088459132206006X","url":null,"abstract":"<p>The calculation of asymptotic directions of approach of cosmic ray particles is an important tool in the determination of the rigidity cutoff for a given geographical site. We present the results of computations of the asymptotic latitude and asymptotic longitude and the magnetic rigidity cutoff for the eight airports (Apatity, Oulu, Warsaw, Lae, Buenos Aires Wellington and Mc Murdo) located at different latitudes and longitudes based on the numerical integration of equations of motion of charged particles of cosmic radiation in the Earth’s magnetic field. The initial distance from the center of the Earth was taken as 20 km above the surface. At about this altitude, most cosmic rays undergo nuclear collisions. Calculations were made for the model of the International Geomagnetic Reference Field (IGRF) in 2015.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 6","pages":"300 - 315"},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4333862","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}

{"title":"Geospace Perturbations that Accompanied Rocket Launches from the Baikonur Cosmodrome","authors":"Y. Luo,&nbsp;L. F. Chernogor,&nbsp;Y. H. Zhdanko","doi":"10.3103/S0884591322060046","DOIUrl":"10.3103/S0884591322060046","url":null,"abstract":"<div><p>The launch of a rocket requires an energy comparable to the energy of many natural processes. For large rockets, the energy release reaches 10–100 TJ, and the power of engines reaches 0.1–1 TW. The energy release per unit volume is much higher than the specific energy content and energy release of all natural processes. During the launch and flight of a large rocket, disturbances in the substratum, the atmosphere, the ionosphere, and even in the magnetosphere occur. Effects from rocket engine burns have been studied for more than 60 years. Research results have been published in hundreds of articles, handbooks, and monographs. It turns out that the effects produced exhibit diverse geophysical phenomena. The effects near the rocket trajectory, namely, the regions of depressed electron density (ionospheric holes), and the generation of infrasound and atmospheric gravity waves (density waves) are investigated better than other effects. Great attention has been paid to studying the geomagnetic effect. The following methods have been used in studies: the Doppler effect, the Faraday, incoherent scattering, ionosonde, magnetometric methods, etc. The effects accompanying the launches and flights of rockets are being actively studied even now. For many years, large-scale (1 to 10 Mm) disturbances that occur after rocket launches have been studied. Their study makes it possible to better understand the mechanisms of the propagation of disturbances from a rocket over global distances, the interaction of subsystems in the Earth–atmosphere–ionosphere–magnetosphere system, and the ecological consequences of rocket engine burns. Disturbances occurring in the atmosphere and geospace substantially depend on the state of the atmospheric–space weather, time of day, season, and phase of the solar cycle. Even with the launch of two identical rockets, disturbances in the mentioned system can be very different. It should be borne in mind that rockets differ in power, trajectories, fuel composition, and the location of cosmodromes. Therefore, studying the response of subsystems to rocket launches and flights remains an urgent problem. The purpose of this study is to describe the results of an analysis of the ionospheric effects of the Soyuz and Proton rockets launched during the 24th cycle of solar activity from the Baikonur Cosmodrome. To observe the effects in the ionosphere caused by the launch of the Soyuz and Proton rockets from the Baikonur Cosmodrome, a vertical sounding Doppler radar was used. As a rule, measurements are carried out at two fixed frequencies of 3.2 and 4.2 MHz. The smaller of them is effective when studying the dynamic processes in the E and F1 layers, and the larger one is effective when studying the F1 and F2 layers. The parameters of ionospheric disturbances that followed the launches of 81 Soyuz rockets and 53 Proton rockets from the Baikonur Cosmodrome in 2009–2021 are analyzed. It is confirmed that there are several groups of delay ","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 6","pages":"287 - 299"},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4328699","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}

{"title":"Quantitative Analysis of the Spectrum of HD 108564","authors":"Y. V. Pavlenko","doi":"10.3103/S0884591322060058","DOIUrl":"10.3103/S0884591322060058","url":null,"abstract":"<p>A quantitative analysis of the spectrum of HD 108564 is performed. It is a star of the main sequence of spectral class K5V, the atmosphere of which is depleted in metals. The high-quality observed HARPS spectra are downloaded from the ESO archive. Abundances of elements in the atmosphere are obtained by fit of observational profiles of the C I lines and selected lines of the C₂ molecules, and the O I, Ca I, Si I, Sc II, Cr I, CI, OI, Na I, Mg I, Si I, Ca I, Sc II, Ti I, Ti II, Cr I, Mn I, Fe I, Fe II, Co I, Ni I, Cu I, and Zn I. Abundances are determined iteratively, with a recalculation of the input parameters, which are effective temperature <i>T</i>_eff  at a fixed value of gravity log<i>g</i> (or log <i>g</i> for a fixed <i>T</i>_eff value). The effect of variations of <i>T</i>_eff  or log <i>g</i>, which provide the same abundances of <i>A</i>(Fe I) and <i>A</i>(Fe II), on the abundances of other elements are determined. The obtained results indicate an excess of light elements (C, O, and Si) compared to the group of iron. The absence of the lithium line at 670.8 nm is confirmed with an estimate of <i>A</i>(Li) &lt; –12.5 for the upper limit of lithium abundance in the abundance scale, in which the sum of all abundances is 1.0. The determined radial velocity equal to <i>V</i>_rad = 111.21 km/s is consistent with the known estimates of other researchers. Apparent rotation velocity <i>V</i> sin <i>i</i> = 1.12 ± 0.5 km/s is determined.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 6","pages":"316 - 327"},"PeriodicalIF":0.5,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4650240","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}

{"title":"Properties of Acoustic-Gravity Waves at the Boundary of Two Isothermal Media","authors":"A. Fedorenko, E. I. Kryuchkov, O. Cheremnykh, S. Melnychuk, I. Zhuk","doi":"10.15407/kfnt2022.06.079","DOIUrl":"https://doi.org/10.15407/kfnt2022.06.079","url":null,"abstract":"The properties of evanescent acoustic-gravity waves that can propagate along the interface between two isothermal half-spaces with different temperatures are studied. In such a model, the condition of a simultaneous decrease in the wave energy density below and above the interface between the media is not satisfied for the known surface f mode. This study shows that it is possible to implement evanescent waves in the form of combinations of f modes and pseudo-modes ( f p modes) for both half-spaces at the interface between two isothermal media. The cross-linking of solutions at the interface depends on the wave spectral parameters and the magnitude of the temperature jump. At the interface, the wave properties change with an increase in the wavelength and their dispersion and polarization acquire features characteristic of acoustic-type waves. These differences are manifested not only in the dispersion dependence of the waves but also in the change in their amplitudes with height, polarization, and velocity divergence at the interface between the media. It is also found for large temperature differences between the lower and upper half-spaces that there is a spectral region in which the solutions satisfying the boundary condition cannot simultaneously decrease in energy below and above the interface. In this region of the spectrum, the f p modes with a decreasing energy in the upper half-space and the f modes with an increasing energy in the lower half-space are joined at the interface. The considered waves at the interface between two media can be observed in the stratified atmosphere at altitudes with a sharp temperature change, for example, in the lower part of the Earth’s thermosphere or in the chromosphere–corona transition region on the Sun.","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 1","pages":"340-350"},"PeriodicalIF":0.5,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67115862","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}

{"title":"Kinetic Alfvén Waves’ Generation in Front of the Earth’s Main Shock Wave","authors":"P. P. Malovichko,&nbsp;Yu. V. Kyzyurov","doi":"10.3103/S0884591322050063","DOIUrl":"10.3103/S0884591322050063","url":null,"abstract":"<p>We investigated the possibility of generating kinetic Alfvén waves by beams of high-speed protons in front of the Earth’s main shock wave. An analytical solution is obtained for the hose-type instability of kinetic Alfvén waves caused by the beam’s dynamic pressure. The effect of the temperature of high-speed beams and the temperature of solar wind protons on the characteristics of the generated disturbances is studied. The temperature has a significant effect on the transverse scales of disturbances: the higher the temperature of the beam protons and the lower the temperature of the surrounding plasma, the more stringent the restrictions imposed on the transverse wavelength scales. The development of instability during the propagation of beams of reflected, intermediate, and diffused protons in the region ahead of the Earth’s main shock wave is considered. The dynamics of the movement of disturbances in this region are analyzed.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 5","pages":"231 - 239"},"PeriodicalIF":0.5,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4780151","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}

{"title":"Hyades Kinematics and the Relationship Between Galactic Coordinates and its Angular Distance from the Apex with Gaia EDR3","authors":"Amnah S. Al-Johani,&nbsp;W. H. Elsanhoury,&nbsp;Afaf Al-Juhani,&nbsp;Ghada Al-Qadhi,&nbsp;Manar Al-Anazi,&nbsp;Sarah Al-Balwi,&nbsp;Sarah Al-Hamdi,&nbsp;Shorouq Al-Qahtani,&nbsp;Wejdan Al-Shehri","doi":"10.3103/S0884591322050026","DOIUrl":"10.3103/S0884591322050026","url":null,"abstract":"<p>In this paper, we have improved the Hyades members with aid of the Gaia EDR3 source. We have studied their kinematics, including computations of the convergent point with AD-diagram method such as <span>(left( {{{A}_{0}},~{{D}_{0}}} right) = left( {79^circ .48 pm 0^circ .11,~,,6^circ .85 pm 0^circ .38} right))</span>, their spatial velocities <span>(U,~V,~W,{text{(km}};{{{text{s}}}^{{ - 1}}}{text{)}})</span>, their morphology with 3D. A relation was established for Hyades stars between their Galactic coordinates <span>(left( {l,~b} right))</span> and the angular distances <span>(left( {{lambda }} right))</span> from the vertex. The precision criteria of this relation are very satisfactory and a correlation coefficient of value <span>( approx 0.90)</span> was found which proves that the attributes are completely related linearly.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 5","pages":"240 - 247"},"PeriodicalIF":0.5,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5073079","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}

{"title":"Characteristic Features of the Magnetic and Ionospheric Storms on December 21–24, 2016","authors":"Y. Luo,&nbsp;L. F. Chernogor","doi":"10.3103/S0884591322050051","DOIUrl":"10.3103/S0884591322050051","url":null,"abstract":"<p>Solar storms accompanied by solar flares, coronal mass ejections, and high-speed flows result in considerable disturbances in the Sun–interplanetary medium–magnetosphere–ionosphere–atmosphere–Earth (internal geospheres) system. As a result, geospace storms with synergistically interacting magnetic, ionospheric, atmospheric, and electrical storms arise in our planet. Magnetic and ionospheric storms have been studied for a long time, but atmospheric storms and electrical storms have been studied considerably to a less extent. Geospace storms and their components exhibit significant variability. It may be asserted that no identical two storms exist. Therefore, a comprehensive study of each new geospace storm and its manifestations and features is an urgent scientific issue. This will contribute to a process of their adequate simulation and, in the long term, forecasting. The purpose of this article is to describe the observed features of the ionospheric and magnetic storms accompanying the geospace storm on December 21–24, 2016. The state of the geomagnetic field has been observed via the fluxgate magnetometer located at the Magnetometer Observatory of the Karazin Kharkiv National University (49°38′ N, 36°56′ E). The dynamics of the ionospheric plasma has been monitored by a vertical incidence Doppler radar and a digisonde located at the Radio Physics Observatory of the Karazin Kharkiv National University (49°38′ N, 36°20′ E). The Doppler radar operate at 3.2 and 4.2 MHz; however, only measurements performed at 3.2 MHz are given below, since a frequency of 4.2 MHz turned out to be inefficient at nighttime when F2 layer critical frequency median <i>f</i>_{0 F2} ≈ 2 MHz, which prevented signal reflection from the ionosphere even at 3.2 MHz. Prior to the beginning of the magnetic storm on December 20, 2016, the level of the <i>H</i> and <i>D</i> components rarely exceeded 0.2–0.7 nT. The sudden commencement of a storm between 06:00 and 10:00 UTC virtually did not affect this level. During the second half of the day on December 21, 2016, the level of exhibited sporadic fluctuations increased from approximately 1 to 3–4 nT. During the next few days, up to December 25, 2016, their level showed variations mostly from approximately 1 nT to approximately 2 nT. Increases in the level were predominantly observed in the period from 05:00 to 15:00 UTC for the <i>H</i> component and from 10:00 to 20:00 UTC for the <i>D</i> component. The weak (power 20 GJ/s and energy approximately 0.45 PJ) geospace storm in the period of December 21–24, 2016, was accompanied by a moderate positive ionospheric storm, as well as by three negative ionospheric storms, one of which was very strong, and the other two were strong and moderate. The geospace storm was accompanied by a moderate magnetic storm with an energy of approximately 2 PJ and a power of approximately 56 GW. The positive ionospheric storm barely affects the level of the signal reflected from the ionospher","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 5","pages":"262 - 278"},"PeriodicalIF":0.5,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4776689","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}