The sequence of evolution of the protoplanetary gas-and-dust disk around the parent star includes, according to modern concepts, its compression in the central plane and decay into separate dust condensations (clusters) due to the occurrence of various types of instabilities. The interaction of dust clusters of a fractal structure during their collisions is considered as a key mechanism for the formation and growth of primary solids, which serve as the basis for the subsequent formation of planetesimals and embryos of planets. Among the mechanisms contributing to the formation of planetesimals, an important place belongs, along with gravitational instability, hydrodynamic instabilities, in particular, the socalled streaming instability of the two-phase gas-dust layer due to its ability to concentrate dispersed particles in dense clots. In contrast to a number of existing models of streaming instability, in which dust particles are considered structurally compact and monodisperse, this paper proposes a more realistic model of polydisperse particles of fractal nature, forming dust clusters as a result of coagulation. The instability of the dust layer in the central plane of the protoplanetary disk under linear axisymmetric perturbations of its parameters is considered. A preliminary conclusion can be drawn that the proposed model of dust fractal aggregates of different scales increases the efficiency of linear growth of hydrodynamic instabilities, including the streaming instabilities associated with the difference between the velocities of the dust and gas phases.
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Solar System Research - For the purpose of mathematical simulations of the formation processes for planetesimals in the Solar protoplanetary disk, statistical thermodynamics for nonextensive... 相似文献
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A. V. Kolesnichenko 《Solar System Research》2008,42(5):391-404
A stochastic-thermodynamic approach to the derivation of the generalized fractional Fokker—Planck—Kolmogorov (FFPK) equations
is considered. The equations describe turbulent transfer processes in a subsystem of turbulent chaos on the basis of fractional
dynamics, which takes into account the structure and metric of fractal time. The actual turbulent motion of a fluid is known
to be intermittent, since it demonstrates the properties that are intermediate between the properties of regular and chaotic
motions. On the other hand, the process of the flow turbulization may be non-Markovian because of the multidimensional spatiotemporal
correlations of pulsating parameters; in a physical language, this means that the process has a memory. The introduction of
fractional time derivatives into the FFPK kinetic equations, used to find the probability distribution functions for different
statistical characteristics of structured turbulence, makes it possible to use an unified mathematical formalism in considering
the effects of memory, nonlocality, and time intermittence, with which we usually associate the presence of turbulent bursts
against the background of less intense low-frequency oscillations in the background turbulence. This study is aimed at creating
representative models of space and natural media. It is a development of the synergetic approach to the modeling of structured
turbulence in astrogeophysical systems, which has been developed by the author in a series of papers (Kolesnichenko, 2002–2005). 相似文献
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O. G. Savichev L. G. Kolesnichenko E. V. Saifulina 《Geography and Natural Resources》2011,32(4):333-336
Presented are the results from investigating the chemical composition and quality of surface waters and bottom sediments in
the Taz-Yenisei interfluve. The mean values of hydrochemical and geochemical indicators were determined, which can be used
as background values in assessing the actual and allowable anthropogenic impact on water bodies. The elevated contents of
a number of metals and organic and biogenic substances in the water are largely associated with the climatic conditions favorable
for accumulation in aqueous medium of plant remains and products of their decomposition. 相似文献
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Shatsky V. S. Ragozin A. L. Wang Q. Su W. Ilyin A. A. Kolesnichenko M. V. 《Doklady Earth Sciences》2023,507(3):S365-S374
Doklady Earth Sciences - Study of xenoliths of crustal rocks from the Novinka kimberlite pipe (Upper Muna kimberlite field) showed that the crust at different levels is composed of pyroxene and... 相似文献
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G. P. Bogatyrev I. V. Kolesnichenko G. V. Levina A. N. Sukhanovsky 《Izvestiya Atmospheric and Oceanic Physics》2006,42(4):423-429
Laboratory experiments have been carried out to investigate conditions for the generation of a large-scale spiral vortex from a localized heat source in a rotating fluid. It is shown that there is a threshold for the excitation of a vortex rotating much more rapidly than the cuvette. The influence of the intensities of convection and background rotation on the excitation threshold of a spiral vortex has been investigated for various liquids in cuvettes of different geometry. In all experiments, the threshold of vortex excitation corresponds to turbulent convection states and a relatively slow background rotation and practically does not depend on the Prandtl number. The influence of the spatial distribution of temperature in the heating area on the threshold of vortex generation has been revealed. 相似文献
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Solar System Research - A generalization of Chandrasekhar’s integral theorems on the equilibrium for matter and blackbody radiation in a protostellar gravitating spherically symmetric cloud... 相似文献
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Solar System Research - The aim of this paper is to construct the thermodynamics of open quantum systems of elementary Bose-gas particles in the framework of nonextensive Tsallis statistics based... 相似文献
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