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1.
Lineament analysis is applied to map the pattern of the Obruchev fault system in the Buguldeika Village area, where several fault zones (Olkhon, Primorsky, Prikhrebtovyi, Buguldeika, and Kurtun) make up a junction. As inferred from the predominant directions of genetically related lineaments, the Olkhon, Primorsky, and Prikhrebtovyi faults originated under NW-SE extension and compression. The extension and compression settings within these zones are reconstructed by analysis of lineaments that have prominent and poor geomorphic expression, respectively. However, the pattern of lineaments well expressed in the surface topography within a weakly deformed block corresponds to reverse slip, while that of poorly pronounced lineaments corresponds to left-lateral strike slip. The study confirms the idea that the latest extension (rifting) stage in the Baikal region reactivated fault zones but did not deform blocks. The blocks store record of residual deformation produced by previous settings of regional compression and shear. The obtained results agree with earlier tectonophysical analysis of faults and fractures in the area and prove the applicability of the suggested approach to map the fault patterns and reconstruct their respective stress settings in areas that underwent multiple deformation events of different ages. 相似文献
2.
A. N. Kryshtal A. D. Voitsekhovska S. V. Gerasimenko O. K. Cheremnykh 《Kinematics and Physics of Celestial Bodies》2017,33(4):149-165
The studied region is a part of the current circuit of a magnetic loop in a solar active region in the altitude range of 1400–2500 km above the photosphere. At the earliest stage of development of a flare process, the magnetic field of the loop was assumed to be stationary and uniform in the interval corresponding to weak fields (the so-called deca-hectogauss fields). The conditions for emergence and development of instability of the second harmonic of Bernstein modes in this previously unexamined region were determined. This instability (and low-frequency instabilities emerging later) was assumed to be caused by the sub-Dreicer electric field of the loop, while pair Coulomb collisions were considered to be the major factor hindering its development. The obtained extremely low instability thresholds point to the possibility of subsequent emergence of low-frequency instabilities (and plasma waves corresponding to them) with much higher threshold values against the background of saturated Bernstein turbulence. The frequency of electron scattering by turbulence pulsations in this scenario normally exceeds the frequency of pair Coulomb (primarily ion–electron) collisions. Both the quasistatic sub-Dreicer field in the loop and the weak spatial inhomogeneity of plasma temperature and density were taken into account in the process of derivation and analysis of the dispersion relation for low-frequency waves. It was demonstrated that the solutions of the obtained dispersion relation in the cases of prevalent pair Coulomb collisions and dominant electron momentum losses at pulsations of saturated Bernstein turbulence are morphologically similar and differ only in the boundary values of perturbation parameters. In both cases, these solutions correspond to the two wave families, namely, kinetic Alfven waves and kinetic ion acoustic waves. These waves have their own electric fields and may play the important role in the process of preflare acceleration of energetic electrons. 相似文献
3.
D. I. Mendzhul O. V. Agapitov O. K. Cheremnykh 《Kinematics and Physics of Celestial Bodies》2013,29(3):107-119
The ray trajectories of waves in the very low frequency (VLF) range in the case of nonducted propagation in the earth’s inner magnetosphere are studied as functions of location of their source region, frequency, and initial angle between the vector of wave normal and intensity vector of external magnetic field. Simulation is performed on the basis of geometric ray tracing approach in multicomponent plasma. The parameters of the magnetospheric medium were calculated using a diffusion model of the concentration distribution of plasma components and the International Geomagnetic Reference Field (IGRF) model. It is shown that the magnetospheric wave reflection can occur if the lower hybrid resonance frequency is greater than its own wave frequency (ω LHF > ω), i.e., at the latitudes λ ≈ 50°. The simulation results confirm that the quasi-longitudinal approximation cannot be used to describe the magnetospheric whistler propagation. We present simulations of propagation of chorus-type wave magnetospheric emissions that were performed using realistic wave distributions over initial parameters. In particular, we present distributions of chorus waves over directions of wave vector as functions of geomagnetic latitude; these distributions are required to study the particle scattering and acceleration processes in the radiation belts. Our results well agree with CLUSTER satellite measurements. 相似文献
4.
We analyse the behaviour of linear magnetohydrodynamic perturbations of a coronal arcade modelled by a half-cylinder with an azimuthal magnetic field and non-uniform radial profiles of the plasma pressure, temperature, and the field. Attention is paid to the perturbations with short longitudinal (in the direction along the arcade) wavelengths. The radial structure of the perturbations, either oscillatory or evanescent, is prescribed by the radial profiles of the equilibrium quantities. Conditions for the corrugation instability of the arcade are determined. It is established that the instability growth rate increases with decreases in the longitudinal wavelength and the radial wave number. In the unstable mode, the radial perturbations of the magnetic field are stronger than the longitudinal perturbations, creating an almost circularly corrugated rippling of the arcade in the longitudinal direction. For coronal conditions, the growth time of the instability is shorter than one minute, decreasing with an increase in the temperature. Implications of the developed theory for the dynamics of coronal active regions are discussed. 相似文献
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6.
Sobisevich A. L. Presnov D. A. Tubanov Ts. A. Cheremnykh A. V. Zagorskiy D. L. Kotov A. N. Numalov A. S. 《Doklady Earth Sciences》2021,496(1):76-79
Doklady Earth Sciences - The results of a geophysical field experiment on the ice sheet of Lake Baikal are presented. The experiment was carried out in order to obtain a better understanding of... 相似文献
7.
A. A. Loginov N. N. Sal’nikov O. K. Cheremnykh Ya. I. Zyelyk N. V. Maslova 《Kinematics and Physics of Celestial Bodies》2011,27(5):217-223
The mechanism of the generation of the poloidal flux on the Sun caused by the differential rotation of the star is considered.
Ranges have been found in which the poloidal flux is generated. 相似文献
8.
Conditions for the realization of ULF waves with different polarization are formulated and verified with the use of observational
data from the spacecrafts which performed measurements in the earth’s magnetosphere. It is shown that the conditions formulated
are in good agreement with observed wave parameters. 相似文献
9.
This paper analyzes transversal small-scale perturbations in arbitrary three-dimensional (3D) spatially nonuniform space plasma
systems with magnetic surfaces and deduces a system of equations for these perturbations. It shows that a dipole magnetic
field can have perturbations of two different polarizations. Within dipole geometry, it derives equations for MHD-eigenmodes
and investigates stability of the perturbations. 相似文献
10.
O. K. Cheremnykh D. Yu. Klimushkin D. V. Kostarev 《Kinematics and Physics of Celestial Bodies》2014,30(5):209-222
The problem of propagation of azimuthally small-scale ULF modes in plasma with 1D inhomogeneity and variable curvature of magnetic lines of force is analyzed. The propagation regions and the transverse structure of stable Alfven and cusp modes, as well as unstable ballooning modes, are determined. It is shown that long-living ballooning and cusp modes can exist. Our results qualitatively describe the behavior of ULF modes with continuous spectrum in the geomagnetosphere and can be used for interpretation of spacecraft and SuperDARN radar measurement data. 相似文献