Kinematics and Physics of Celestial Bodies最新文献

{"title":"Impact of a Disc and Drag Forces on the Existence Linear Stability of Equilibrium Points and Newton-Raphson Basins of Attraction","authors":"Saleem Yousuf,&nbsp;Ram Kishor","doi":"10.3103/S0884591322030060","DOIUrl":"10.3103/S0884591322030060","url":null,"abstract":"<p>This paper presents a study of zero velocity curves, linear stability analysis and basins of attraction corresponding to the equilibrium points in the Sun-Jupiter system with asteroid belt and β-Pictoris system with dust belt, respectively under the influence of perturbing factors in the form of Poynting-Robertson drag (P-R drag), solar wind drag and a disc, which is rotating about the common center of mass of the system. Zero velocity curves are obtained and it is observed that in the presence of perturbing factors, the prohibited regions of the motion of infinitesimal mass get disturbed. Again, linear stability and effects of perturbing factors are analyzed for the triangular equilibrium points. It is noticed that because of P-R drag, triangular equilibrium points become unstable within the stability range. Finally, the Newton-Raphson basins of attraction corresponding to the equilibrium points are computed and it is found that in the presence of the disc, geometry of the basins of attraction gets change, whereas the effects of remaining perturbing factors on the structure of basins of attraction are very small.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 3","pages":"166 - 180"},"PeriodicalIF":0.5,"publicationDate":"2022-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4937949","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":"Physical Effects of the Yushu Meteoroid: 1","authors":"L. F. Chernogor","doi":"10.3103/S0884591322030035","DOIUrl":"10.3103/S0884591322030035","url":null,"abstract":"<p>The purpose of this article was to evaluate the mechanical, optical, and gasdynamic effects that accompanied the passage and explosion of the Yushu meteoroid. The explosion occurred over a sparsely populated area, Qinghai Province (Tibetan Plateau, People’s Republic of China). According to NASA, the initial kinetic energy of the celestial body was approximately 9.5 kt TNT or 40 TJ. Approximately 4.9 TJ, i.e., 12.25% of the initial kinetic energy of the body, was converted into the energy of the light flash. The projections of the velocity of the meteoroid are as follows: <i>v</i>_<i>x</i> = –2.6 km/s, <i>v</i>_<i>y</i> = 5.9 km/s, and <i>v</i>_<i>z</i> = –12.1 km/s. They are used to estimate the angle of inclination of the trajectory to the horizon, which is approximately 5°. Using the explosion height of 35.5 km and the inclination angle, the density of the matter is estimated to be close to that of an ordinary chondrite (approximately 3.5 t/m³). Knowledge of the kinetic energy and velocity allows us to calculate the mass of the meteoroid (432 t) and its characteristic size (6.2 m). The energy of the processes, as well as mechanical, optical, and gasdynamic effects of the celestial body, are analyzed. The main release of energy accompanying the deceleration of fragments of the body destroyed at a dynamic pressure of ~1 MPa took place in a 17.2 km long area at a height of approximately 35 km. A quasi-continuous fragmentation and a power law of the distribution of the mass of the fragments are assumed. The main parameters of ballistic and explosive shock waves are estimated. With a Mach number of 45, the radius of the ballistic shock wave was approximately 280 m, and the fundamental period was 2.6 s, which increased from 9.5 to 30.1 s due to dispersion as the distance traveled by the wave increased from 50 to 5000 km. The radius of the cylindrical and spherical explosion waves was approximately 0.8 and 2 km, respectively, and the fundamental period was 7.5 and 18.8 s. This period increased from 21.1 to 66.7 s as the distance increased from 50 to 5000 km. Near the meteoroid terminal point, the relative overpressure was maximal. It decreased with decreasing height, and increased with increasing height until approximately 120–150 km, where it reached ~10–20 percent and then decreased to a few percent. The absolute value of the overpressure for the spherical wave was maximal near the explosion height, then it decreased as the height decreased to 15 km, then increased again. At the epicenter of the explosion, it was approximately 310 Pa for a cylindrical wave or ~48.5 Pa for a spherical wave, which is insufficient to damage ground objects. With increasing height, the overpressure decreased from many tens of pascals to micropascals. The average power of a light flash with a duration of approximately 1.26 s was 3.9 TW, the power flux density near the fireball, more precisely, a 3.4 km long cone with a diameter ","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 3","pages":"132 - 147"},"PeriodicalIF":0.5,"publicationDate":"2022-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4941824","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":"Bands of NaH lines in Spectra of Late Type Stars","authors":"Yu. P. Lyubchyk,&nbsp;Ya. V. Pavlenko,&nbsp;O. K. Lyubchyk,&nbsp;H. R. A. Jones","doi":"10.3103/S0884591322030059","DOIUrl":"10.3103/S0884591322030059","url":null,"abstract":"<p>The absorption of radiation by systems of NaH molecule bands in the atmospheres of late-type stars is modeled. Calculations of synthetic spectra with model atmosphere parameters, which corresponds to M stars, show that the lines of this molecule form notable spectral details approximately the same intensity at wavelengths from λ ≈ 380 nm to almost ~1100 nm. The recently calculated parameters of the NaH molecule from the Exomol database, as well as a new value of the dissociation potential of this molecule <i>D</i>₀ = 1.975, were used in the calculations. The dependences of the calculated spectral energy distributions on the dissociation potential of the NaH molecule and on the parameters of the stellar atmospheres (<i>T</i>_eff, log <i>g</i>, [Fe/H]) were considered. Analysis of synthetic spectra shows that the lines of the NaH molecule become weak with temperature increasing and gravity decreasing in the stellar atmosphere. Thus, sodium hydride lines cannot be observed either in stars with effective temperatures corresponding to early M stars nor in M giants. NaH lines should appear only in the spectra of cold dwarfs, although the strong absorption of other molecules (TiO, CrH, and FeH) in visible and near-infrared region of the spectrum and absorption by atoms in the blue region make the NaH lines' detection a very complicated task. The energy distribution in the spectrum of the red dwarf VB 10 (M8V) in the blue region of the spectrum is modeled. The results of the analysis show that, under normal conditions and close to the solar chemical composition, NaH molecules provide only an additional component in the opacity of the spectra of cold dwarfs and substellar objects.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 3","pages":"159 - 165"},"PeriodicalIF":0.5,"publicationDate":"2022-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4936736","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":"On the Nonlinear Interaction of Low-Frequency Kinetic Plasma Waves in the Preflare Atmosphere of the Solar Active Region","authors":"O. N. Kryshtal,&nbsp;A. D. Voitsekhovska","doi":"10.3103/S0884591322030047","DOIUrl":"10.3103/S0884591322030047","url":null,"abstract":"<p>Necessary conditions for the appearance of decay instability of low-frequency kinetic Alfven waves in loop structures of an active region on the Sun before a flare are obtained. On the basis of the transcendental dispersion equation obtained using the synchronism conditions and additional conservation laws, an expression is obtained for the nonlinear growth rate of the decay instability of the initial kinetic Alfven wave (KAW) to the secondary KAW and the kinetic ion-acoustic wave (KIAW). Boundary values of the reduced amplitude of the initial KAW in the preflare atmosphere of an active region (AR) are obtained. It was assumed in the calculations that the waves involved in the process in the AR under study appear due to the development of instability caused by the presence of a weak large-scale (sub-Dreicer) electric field and drift motions of the plasma due to spatial inhomogeneities of its temperature and density. It is shown that, for a certain type of semiempirical model of the solar atmosphere, kinetic Alfven and kinetic ion-acoustic waves can be generated during the linear stage of instability development. In this case, the process of wave generation can take place both in plasma with purely Coulomb conductivity and in the presence of small-scale Bernstein turbulence in it. To “trigger” the instability, relatively low values of plasma nonisothermality and a very low threshold value of the reduced amplitude of the sub-Dreicer electric field are required. The possibility of the appearance of undamped kinetic waves of small amplitude in the region under study is proven.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 3","pages":"148 - 158"},"PeriodicalIF":0.5,"publicationDate":"2022-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4936737","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 Influence of the Earth’s Atmosphere Rotation on the Spectrum of Acoustic-Gravity Waves","authors":"O. K. Cheremnykh,&nbsp;S. O. Cheremnykh,&nbsp;D. I. Vlasov","doi":"10.3103/S0884591322030023","DOIUrl":"10.3103/S0884591322030023","url":null,"abstract":"<p>It was shown in a recent study [11] that taking into account the rotation of the Earth’s atmosphere leads to the appearance of a new region of evanescent waves with a continuous frequency spectrum on the diagnostic diagram of acoustic-gravity waves. The region is located below the lower limit of gravity waves, which is equal to <span>(2Omega )</span> for all wavelengths, where <span>(Omega )</span> is the angular frequency of the atmospheric rotation. This result was obtained for high-latitude regions of the atmosphere in which one can be limited to considering only the vertical component of the Earth’s rotation frequency. This paper shows that taking into account both components of the vector <span>(vec {Omega })</span> of the atmospheric rotation frequency <span>(vec {Omega })</span>—horizontal, <span>(Omega cos varphi ,)</span> where <span>(varphi )</span> is the local latitude, and vertical, <span>(Omega sin varphi )</span>—the dominant role in the acoustic-gravity wave propagation is played by the vertical component. It is shown that the horizontal component leads to a negligible modification of the boundaries of the regions of acoustic and gravity waves on the diagnostic diagram. It is also shown that the vertical component of the frequency affects most strongly the lower limit of gravity waves, which depends on the latitude of the observation site for all wavelengths and is equal to 2<span>(Omega sin varphi )</span>.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 3","pages":"121 - 131"},"PeriodicalIF":0.5,"publicationDate":"2022-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4941456","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":"Ionospheric Processes during the Partial Solar Eclipse above Kharkiv on June 10, 2021","authors":"L. F. Chernogor,&nbsp;K. P. Garmash","doi":"10.3103/S0884591322020039","DOIUrl":"10.3103/S0884591322020039","url":null,"abstract":"<p>A solar eclipse (SE) provides a researcher with a rare opportunity to follow the dynamics of the Earth’s system (its shells)—the atmosphere, the ionosphere, and the magnetosphere—and variations in the geophysical fields over an interval of a few hours. Different solar eclipses induce significantly different disturbances in this system. The parameters of these disturbances depend on the onset time of a solar eclipse, the state of space weather, the season, the solar cycle phase, the geographic coordinates, and the degree of the solar disk occultation during a solar eclipse. It should be kept in mind that each of the SEs exhibits its own individual characteristics. The purpose of this paper is to analyze the results of ionosonde observations of the ionospheric disturbances accompanying the SE above the city of Kharkiv on June 10, 2021. At the city of Kharkiv, the maximal observed magnitude of the SE was <i>М</i>_max ≈ 0.11 (more precisely, 0.112) and the relative area of the solar disk occultation was <i>А</i>_max ≈ 4.4%. The eclipse started at 10:42 UT (13:42 LT) and ended at 12:12 UT (15:12 LT). The maximal magnitude was observed at 11:28 UT (14:28 LT). To study the features of variations in the virtual heights and the frequencies, we used a digital ionosonde located at the Radio Physical Observatory of the V. N. Karazin Kharkiv National University. The analysis of the space weather showed that, during the SE, as well as at the reference time intervals on June 6 and 9, 2021, the space weather conditions were favorable for observing wave disturbances, which is evidenced by the index value <i>K</i>_p ≈ 0.3. The frequency and altitude characteristics of the ionosphere obtained by vertical sounding were analyzed, and the features of the ionospheric processes, which accompanied the partial SE but were absent on the reference day, were determined. During the SE, wave activity in the ionosphere became stronger. The wave trains, which were observed at an altitude of the <i>F</i>₂ layer maximum, had periods of 5 and 14 min, while the relative amplitudes of oscillations in the electron density were 0.6 and 1.25%, respectively. At an altitude of 240 km, the relative amplitude of waves with a period of ~14 min increased by 3%. The 14-min period pertains to the atmospheric gravitaty waves, while the 5-min period pertains to the waves of electromagnetic nature. A sharp and considerable increase (from 380 to 560 km) in the virtual height of the radio wave reflection from the <i>F</i>₂ region was observed close to the moment of the greatest SE magnitude. A weak decrease (by less than 3.3%) in the electron density, which lagged behind the maximal eclipse magnitude by 12.5 min, was detected. The rates of the electron loss (1.33 × 10^–3 s^–1) and the ion production (3 × 10⁸ m^–3s^–1) were estimated.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 2","pages":"61 - 72"},"PeriodicalIF":0.5,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4729637","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":"Analysis of Actinium Abundances in the Atmosphere of Cepheid HIP13962","authors":"V. F. Gopka,&nbsp;A. V. Shavrina,&nbsp;V. A. Yushchenko,&nbsp;Ya. V. Pavlenko,&nbsp;A. V. Yushchenko,&nbsp;L. V. Glazunova","doi":"10.3103/S0884591322020040","DOIUrl":"10.3103/S0884591322020040","url":null,"abstract":"<p>Actinium is a radioactive element that has an isotope ²²⁷Ac with the longest half-life of 21.772(3) years. It is the third element in the actinoid group, in addition to thorium and uranium, the abundance of which can be studied in the atmospheres of stars. Its presence in the atmosphere of a particular star primarily indicates some mechanism of its production. The first studies of the actinium absorption lines in the spectra of certain stars showed that the appearance of actinium in their spectrum is associated with the presence of deformation of strong lines, such as hydrogen lines and sodium doublet lines. In some cases, profiles of strong lines contain emission components. In the search for actinium absorption lines in the stellar spectra, attention was focused on such class of stars as Cepheids, which are characterized by deformation of strong lines due to pulsations. The absorption lines of actinium were studied in the spectral interval of 378.0–887.7 nm for the runaway star and Cepheid HIP13962 using the spectra obtained in 2014 with a 1.8-m telescope at Bohyunsan Optical Astronomical Observatory (BOAO, South Korea) with a spectral resolution greater than <i>R</i> = 80 000. The archived HIP13962 spectrum for 1995 in the wavelength range of 400.0–680.0 nm with a spectral resolution <i>R</i> = 42 000, which was obtained with the 1.93-m telescope of the Haute Provence Observatory (France), was also used. The modeling showed that the actinium abundance in the atmosphere of HIP13962 log <i>N</i>(Ac) = –1.2 on the hydrogen scale log <i>N</i>(H) = 12.0, with the model atmosphere <i>T</i>_eff = 5930 K, log <i>g</i> = 1.0, <i>V</i>_micro = 6 km s^–1. This value turns out to be 0.2 more at an increase in the effective temperature <i>T</i>_eff = 6250 K: log<i>N</i>(Ac) = –1.0 on the hydrogen scale log<i>N</i>(H) = 12.0.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 2","pages":"100 - 107"},"PeriodicalIF":0.5,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4729028","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":"Convective Line Shifts in the Spectra of Solar-Type Stars","authors":"V. A. Sheminova","doi":"10.3103/S0884591322020064","DOIUrl":"10.3103/S0884591322020064","url":null,"abstract":"<p>The Doppler line shifts in the spectra of the Sun and stars with effective temperatures from 4800 to 6200 K were measured and the average convective (granulation) velocities were estimated. The absolute scale of the line shifts for the stars was established on the basis of the derived dependence of the shifts of solar lines on optical depth. For FGK solar-type stars, curves of convection velocities as a function of the altitude in the atmosphere in a large range of altitudes from 150 to 700 km were obtained for the first time. All these curves indicate a decrease in blue shifts with altitude, which means that the granulation velocities through the photosphere slow down to zero. In the lower chromosphere, red shifts of strong Mg I lines are observed, which indicate a change in the direction of granulation velocities to the opposite and confirm the effects of reversal of granulation at altitudes above 600 km. In cooler K stars, granulation shifts change with altitude on average from –150 to 100 m/s, while they change more sharply in hotter FG stars from –700 to 300 m/s. The gradient of the line shift curves increases with an increase in the effective temperature and a decrease in gravity, metallicity, and age of the star. The convective velocity of the star averaged over all analyzed altitudes increases from –90 to –560 m/s from colder to hotter stars. It correlates with macroturbulence, asymmetry of spectral lines, and the rotation velocity of the star. We also obtained the radial velocities of the stars and compared them with the SIMBAD data. Large deviations of –21 050 and 1775 m/s were found for the stars HD 102361 and HD 42936, respectively. For the rest of the stars, the deviation does not exceed ±340 m/s, which is probably associated with the use of an average granulation velocity of –300 m/s in the SIMBAD data. Our analysis has shown that the average granulation velocity is not the same for solar-type stars. It is lower in colder stars and higher in hotter stars than the Sun. Therefore, determination of the radial velocities needs to take into account the individual granulation velocities of stars.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 2","pages":"83 - 99"},"PeriodicalIF":0.5,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4732948","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":"Estimation of the Accuracy of Geostationary Satellite Observations","authors":"M. O. Kulichenko,&nbsp;N. V. Maigurova,&nbsp;O. V. Shulga,&nbsp;V. F. Kryuchkovskiy","doi":"10.3103/S0884591322020052","DOIUrl":"10.3103/S0884591322020052","url":null,"abstract":"<p>Continuous monitoring of artificial space objects requires periodic quality control of observational data. Estimating the internal accuracy of observations in the form of an RMS error of positions makes it possible to monitor and detect outliers in primary data array. For artificial satellites of the Earth, the orbital elements calculated at the Research Institute Nikolaev Astronomical Observatory (RI NAO) can be externally compared with the data of the International Laser Ranging Service (ILRS) or the Global Navigation Satellite System (GNSS). Such a comparison makes it possible to detect time synchronization problems and to identify and evaluate systematic errors. At the RI NAO, regular observations of artificial satellites in different orbits using several telescopes have been carried out for more than 10 years, and a catalog of orbital elements in the two-line element (TLE) format is maintained. The software for calculating orbital elements has been developed in cooperation with the Astronomical Observatory of the Odessa National University. This article presents the analysis of the processing results of an array of observations from 149 geostationary satellites (GSS’s). The observations have been made during 2020…2021 using the RI NAO telescope complex. Time synchronization has been provided by the Resolution-T GPS receiver with an RMS error of 40 ns. All GSS observations have been carried out using the combined observation method developed at the RI NAO. A total of 134 461 GSS positions have been obtained for which the residual <i>O–C</i> differences with respect to the orbit calculated at the RI NAO have been determined. The RMS error of the GSS positions in the apparent magnitude range 9^<i>m</i>…13^<i>m</i> is 0.5″ in right ascension and declination. A comparison of the GSS orbital positions calculated from the RI NAO orbital elements and the ILRS website data shows that the differences between the corresponding geocentric Cartesian coordinates at the start of the prediction are <i>dX</i> = 0.72 km, <i>dY</i> = –0.52 km, and <i>dZ</i> = 1.28 km.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 2","pages":"108 - 113"},"PeriodicalIF":0.5,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4729638","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":"Seasonal Features of the Spatial Distribution of Atmospheric Gravity Waves in the Earth’s Polar Thermosphere","authors":"D. I. Vlasov,&nbsp;A. K. Fedorenko,&nbsp;E. I. Kryuchkov,&nbsp;O. K. Cheremnykh,&nbsp;I. T. Zhuk","doi":"10.3103/S0884591322020076","DOIUrl":"10.3103/S0884591322020076","url":null,"abstract":"<p>The features of the spatial distribution of atmospheric gravity waves (AGW) in the polar thermosphere of the Earth are investigated. The research is based on data from direct satellite measurements of the parameters of the neutral atmosphere. According to satellite data, the amplitudes of AGWs that are systematically observed in the polar regions of both hemispheres are usually several times higher than the amplitudes of these waves in the middle and low latitudes. At the same time, the polar AGWs of large amplitudes are recorded against the background of high-speed spatially inhomogeneous wind flows, which indicates their possible amplification caused by interaction with the wind. Based on the analysis of measurement data on the Dynamics Explorer 2 satellite, the relationship between the spatial distribution of the atmospheric gravitational waves and the auroral oval has been revealed. On a large volume of experimental data, seasonal patterns of the distribution of the wave field over the Antarctic and the Arctic have been established. A comparative analysis of the features of the AGWs in the polar thermosphere of both hemispheres for the conditions of the polar day and polar night has been carried out. Some differences in the distribution of the AGWs were noted depending on the Kp-index. It has been suggested that the observed seasonal features of the AGW distribution and its dependence on the level of geomagnetic activity are associated with the restructuring of the polar wind circulation when the conditions of solar illumination and geomagnetic conditions change.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"38 2","pages":"73 - 82"},"PeriodicalIF":0.5,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4729632","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}