Simulating the Propagation of Infrasonic Waves and Estimating the Energy of the Chelyabinsk Meteoroid Explosion Observed on February 15, 2013     

S.?N.?KulichkovEmail author  O.?Ye.?Popov  K.?V.?Avilov  I.?P.?Chunchuzov  O.?G.?Chkhetiani  A.?A.?Smirnov  V.?I.?Dubrovin  A.?A.?Mishenin 《Izvestiya Atmospheric and Oceanic Physics》2018,54(3):293-303

Results obtained from simulating the propagation of infrasonic waves from the Chelyabinsk meteoroid explosion observed on February 15, 2013, are given. The pseudodifferential parabolic equation (PDPE) method has been used for calculations. Data on infrasonic waves recorded at the IS31 station (Aktyubinsk, Kazakhstan), located 542.7 km from the likely location of the explosion, have been analyzed. Six infrasonic arrivals (isolated clearly defined pulse signals) were recorded. It is shown that the first “fast” arrival (F) corresponds to the propagation of infrasound in a surface acoustic waveguide. The rest of the arrivals (T1–T5) are thermospheric. The agreement between the results of calculations based on the PDPE method and experimental data is satisfactory. The energy E of the explosion has been estimated using two methods. One of these methods is based on the law of conservation of the acoustic pulse I, which is a product of the wave profile area S/2 of the signal under analysis and the distance to its source E _I [kt] = 1.38 × 10^–10 (I [kg/s])^1.482. The other method is based on the relation between the energy of explosion and the dominant period T of recorded signal E _T [kt] = 1.02 × (T [s]²/σ)^3/2, where σ is the dimensionless distance determining the degree of nonlinear effects during the propagation of sound along ray trajectories. According to the data, the explosion energy E _I,T ranges from 1.87 to 32 kt TNT.  相似文献   

Influence of Oxygen Ions on the Structure of the Thin Current Sheet in the Earth’s Magnetotail     

Domrin  V. I.  Malova  Kh. V.  Popov  V. Yu.  Grigorenko  E. E.  Petrukovich  A. A. 《Geomagnetism and Aeronomy》2020,60(2):171-183

Geomagnetism and Aeronomy - During geomagnetic substorms, the current sheet in the Earth’s magnetotail can transversely reduce in thickness from a few radii of the Earth (RE) to one to...  相似文献   

Absorption of Photons from Distant Gamma-Ray Sources     

A. N. Popov  D. P. Barsukov  A. V. Ivanchik 《Astronomy Letters》2018,44(10):579-587

Being the largest gravitationally bound structures in the Universe, galaxy clusters are huge reservoirs of photons generated by the bremsstrahlung of a hot cluster gas. We consider the absorption of high-energy photons from distant cosmological gamma-ray sources by the bremsstrahlung of galaxy clusters. The magnitude of this effect is the third in order of smallness after the effects of absorption by the cosmic microwave background and absorption by the extragalactic background light. Our calculations of the effect of absorption by the bremsstrahlung of galaxy clusters have shown that this effect manifests itself in the energy range ~1–100 GeV and can be τ ~ 10^?5 in optical depth.  相似文献   

Color of the Corona Continuum of July 11, 1991     

Kim  I. S.  Krusanova  N. L.  Popov  V. V.  Osokin  A. R.  Mironova  I. V. 《Geomagnetism and Aeronomy》2020,60(4):441-445

Geomagnetism and Aeronomy - The color of the coronal continuum was determined from observations in order to search for manifestations of coronal expansion. A brief review of studies determining the...  相似文献   

Observability of Single Neutron Stars at SRG/eROSITA     

Khokhryakova  A. D.  Biryukov  A. V.  Popov  S. B. 《Astronomy Reports》2021,65(7):615-630

Astronomy Reports - A four-year sky survey with the use of the eROSITA telescope on board the Spektr-RG observatory with focusing optics will provide the best coverage in the soft (0.5–2 keV)...  相似文献   

NSVS 2569022:a peculiar binary among W UMa stars with extremely small mass ratios     

Diana P.Kjurkchieva  Velimir A.Popov  Nikola I.Petrov 《天文和天体物理学研究(英文版)》2018,(10)

Photometric observations of the W UMa binary NSVS 2569022 are presented. The light curve solution reveals that both components are of F spectral type(temperatures T_1= T_2= 6100 K). NSVS2569022 undergoes a total eclipse of W subtype and the mass ratio is well-determined. Its extremely small value of only 0.077 implies that the target will probably experience instability and a possible merger. This value ranks NSVS 2569022 in sixth place among binaries with the smallest mass ratio.Based on an empirical relation of "period – total mass" for low mass-ratio binaries, we estimate the global parameters of NSVS 2569022: masses M_1= 1.17 M⊙and M_2= 0.09 M⊙; radii R_1= 1.19 R⊙and R_2= 0.38 R⊙; luminosities L_1= 1.73 L⊙and L_2= 0.17 L⊙. An analysis of the characteristics of binaries with extremely low-mass ratios is made. NSVS 2569022 turns out to be a peculiar binary among W UMa stars with extremely small mass ratios due to its unexpectedly small fill-out factor of only 0.014(slightly overcontact configuration).  相似文献   

Simulating the influence of an atmospheric fine inhomogeneous structure on long-range propagation of pulsed acoustic signals     

S. N. Kulichkov  I. P. Chunchuzov  O. I. Popov 《Izvestiya Atmospheric and Oceanic Physics》2010,46(1):60-68

The results of simulating the influence of an atmospheric fine structure on the characteristics of acoustic signals propagating throughout the atmosphere for long distances from their sources are presented. A numerical model of an atmospheric fine inhomogeneous structure within the height range z = 20…120 km is proposed to perform calculations. This model and its numerical parameters are based on the current notions of the formation of an atmospheric fine structure due to internal gravity waves. The numerical calculations were performed using the parabolic-equation method. A spatial structure of the acoustic field and the structure of an acoustic signal at long distances from a pulsed source were calculated. It is shown that the presence of an atmospheric fine structure results in a scattering of acoustic signals and their recording in the geometric shadow region. The results of calculations of signal forms are in a satisfactory agreement with data on signals recorded in the geometric shadow region which is formed at a distance of about 300 km from an experimental explosion.  相似文献   

Paleomagnetism of Permian rocks of the Subpolar Urals,Kozhim River: To the history of evolution of the thrust structures in the Subpolar Urals     

A. G. Iosifidi  V. V. Popov 《Izvestiya Physics of the Solid Earth》2017,53(5):619-634

The collections of Permian rocks from sections of the Kozhim River (Asselian, Kungurian, and Ufimian stages) and the Kama River (Ufimian and Kazanian stages) are studied. The paleomagnetic directions determined on the studied structures closely agree with the existing data for the Subpolar Urals and Russian Platform (RP). In the Middle Permian red clays of the Kama River region, the paleomagnetic pole N/n = 28/51, Φ = 47° N, Λ = 168° E, dp = 3°, and dm = 5° is obtained. The analysis of the existing paleomagnetic determinations for the Early and Middle Permian of the Russian and Siberian platforms and Kazakhstan blocks (KBs) is carried out. For the Subpolar Ural sections, the estimates are obtained for the local rotations during the collision of the Uralian structures with the Russian and Siberian platforms and KBs. The amplitudes of the horizontal displacements of the studied structures are, on average, 170 ± 15 km per Middle Permian. The scenario describing the evolution of the horizontal rotations of the structures of Subpolar Urals is suggested.  相似文献   

The nature of magnetic anomalies in subduction zones     

A. M. Gorodnitskii  Yu. V. Brusilovskii  A. N. Ivanenko  K. V. Popov  N. A. Shishkina 《Izvestiya Physics of the Solid Earth》2017,53(5):795-802

The analysis of the magnetic survey data suggests the presence of a frontal zone of intense magnetic anomalies in a number of the Pacific island-arc systems. These zones with amplitudes of 100–300 nT are observed within the Kuril–Kamchatka and Aleutian island arc systems, in Southern and Central America, and Alaska. As demonstrated by the solution of the inverse problem and petromagnetic investigation of the rocks, these zones are presumably related to the serpentinite bodies which form as a result of the hydration of the upper mantle peridotites by the oceanic water penetrating through a system of cracks and fractures into the subducting slab at its bend. The rock magnetic studies show that magnetite is the main carrier of magnetization in these serpentinite bodies. Hydration of the subducting slab also causes hydration of the mantle rocks of the overriding plate with the formation of the magnetized serpentinite wedge. The decompaction of ultrabasic rocks under hydration is marked by a decrease in the gravity field and velocities of elastic waves. As the subducting plate loses water, it becomes embrittled and becomes the localization region for the epicenters of the strongest earthquakes. Magnetic survey can be used for revealing the potential sources of catastrophic earthquakes.  相似文献   

Structure of the current sheets in the near-Mars magnetotail. Maven observations     

E. E. Grigorenko  S. D. Shuvalov  H. V. Malova  V. Yu. Popov  V. N. Ermakov  E. Dubinin  L. M. Zelenyi 《Solar System Research》2017,51(5):347-361

During the last 15 years, the Current Sheets (CSs) have been intensively studied in the tail of the terrestrial magnetosphere, where protons are the dominated ion component. On the contrary, in the Martian magnetotail heavy ions (O⁺ and⁺ ₀) usually dominate while the abundance of protons can be negligible. Hence it is interesting to study the spatial structure and plasma characteristics of such “oxygen” CSs. MAVEN spacecraft (s/c) currently operating on the Martian orbit with a unique set of scientific instruments allows observation of the magnetic field and three-dimensional distribution functions of various ion components and electrons with a high time resolution. In this paper, we analyse nine intervals of the CSs observed by MAVEN in the near-Mars tail at the distances from the planet ~1.5–1R _M , where R _M is the radius of Mars. We analyse the spatial structure of the CSs and estimate their thickness for different magnetic configurations and relative abundance of the heavy and light ions in the sheets. It is shown that, similarly to the CSs in the Earth’s magnetotail, the thickness and complexity of the spatial structure of the Maritan CSs (i.e. the presence of embedded and / or peripheral current structures) depend on the magnetic configuration of the sheets, which, in turn, affects the fraction of the quasi-adiabatic particles in the CSs.  相似文献