共查询到20条相似文献，搜索用时 171 毫秒
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本文对当前应用日益广泛的非线性科学的两个重要分支－分形和混沌动力系统理论－作概述性的介绍，并简介弛这两种非线性方法在天体物理应用的重要结果，特别强调一些于体物理中典型的分形和混沌现象，诸如星系大尺度结构和星系动力学。 相似文献
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本文对当前应用日益广泛的非线性科学的两个重要分支──分形和混沌动力系统理论──作概述性的介绍，并简介了这两种非线性方法在天体物理中应用的重要结果，特别强调一些天体物理中典型的分形和混沌现象，诸如星系大尺度结构（分形）和星系动力学（混沌）。 相似文献
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本文从支配恒星内部物理过程的整套基本方程组出发，应用阵发混沌机制，研究其非线性特性，经过理论分析和数学演算，最后得出结论，即恒星结构方程本身，在一定参数范围内，能够自发出现阵发混沌脉动，这与已观测到的一些脉动变星的不规则光变性质，定性符合得很好。 相似文献
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本文对非线性科学的两个重要分支－分形和混沌－在太阳物理学中的应用情况作了综述，主要内容包括：太阳活动混沌性的揭示；对太阳活动混沌性的可能解释－太阳非线性发电机理论；一些太阳现象的分形描述；耀斑的自组织临界行为研究。最后给出了作者对这一领域工作前景的展望。 相似文献
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分形和混沌理论在太阳物理学中的应用 总被引：1，自引：0，他引：1
本文对非线性科学的两修发支－分形和混沌－在太阳物理学中的应用情况作了综述，主要内容包括；太阳活动混沌性的揭示；对太阳活动混沌的可能解释－太阳非线性发电机；一些太阳现象的分形描述；耀斑的自组织临界行为研究。最后给出了作者对这一领域工作前景的展望。 相似文献
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本从支配恒星内部物理过程的整套基本方程组出发，应用阵发混沌机制，研究其非线性特性，经过理论分析和数学演算，最后得出结论，即恒星结构方程本身，在一定参数范围内，能够自发出现阵发混沌脉动，这与已观测到的一些脉动变星的不规则光变性质，定性符合得很好。 相似文献
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太阳物理学中的分形和混沌 总被引：1，自引：0，他引：1
对非线性科学的两个重要分支；分形和混沌在太阳物理学中的应用情况作了综述信要内容包括；太阳活动混沌性的揭示；对太阳活动混沌性的可能解释－太阳非线性发电机理论；一些太阳现象的分形描述；耀斑的自组织临界行为研究，最后给出了作者对这一领域工作前景的展望。 相似文献
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In this article we treat the 'Extended Sitnikov Problem' where three bodies of equal masses stay always in the Sitnikov configuration.
One of the bodies is confined to a motion perpendicular to the instantaneous plane of motion of the two other bodies (called
the primaries), which are always equally far away from the barycenter of the system (and from the third body). In contrary
to the Sitnikov Problem with one mass less body the primaries are not moving on Keplerian orbits. After a qualitative analysis
of possible motions in the 'Extended Sitnikov Problem' we explore the structure of phase space with the aid of properly chosen
surfaces of section. It turns out that for very small energies H the motion is possible only in small region of phase space and only thin layers of chaos appear in this region of mostly
regular motion. We have chosen the plane (
) as surface of section, where r is the distance between the primaries; we plot the respective points when the three bodies are 'aligned'. The fixed point
which corresponds to the 1 : 2 resonant orbit between the primaries' period and the period of motion of the third mass is
in the middle of the region of motion. For low energies this fixed point is stable, then for an increased value of the energy
splits into an unstable and two stable fixed points. The unstable fixed point splits again for larger energies into a stable
and two unstable ones. For energies close toH = 0 the stable center splits one more time into an unstable and two stable ones. With increasing energy more and more of
the phase space is filled with chaotic orbits with very long intermediate time intervals in between two crossings of the surface
of section. We also checked the rotation numbers for some specific orbits.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Stereo topography of an area near Tyre impact crater, Europa, reveals chaos regions characterised by marginal cliffs and domical topography, rising to 100-200 m above the background plains. The regions contain blocks which have both rotated and tilted. We tested two models of chaos formation: a hybrid diapir model, in which chaos topography is caused by thermal or compositional buoyancy, and block motion occurs due to the presence of near-surface (1-3 km) melt; and a melt-through model, in which chaos regions are caused by melting and refreezing of the ice shell. None of the hybrid diapir models tested generate any melt within 1-3 km of the surface, owing to the low surface temperature. A model of ocean refreezing following melt-through gives effective elastic thicknesses and ice shell thicknesses of 0.1-0.3 and 0.5-2 km, respectively. However, for such low shell thicknesses the refreezing model requires implausibly large lateral density contrasts (50-100 kg m−3) to explain the elevation of the centres of the chaos regions. Although a global equilibrium ice shell thickness of ≈2 km is possible if Europa's mantle resembles that of Io, it is unclear whether local melt-through events are energetically possible. Thus, neither of the models tested here gives a completely satisfactory explanation for the formation of chaos regions. We suggest that surface extrusion of warm ice may be an important component of chaos terrain formation, and demonstrate that such extrusion is possible for likely ice parameters. 相似文献
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This paper presents the approximate general solution of the triple well, double oscillator non-linear dynamical system. This
system is non-integrable and the approximate general solution is calculated by application of the Last Geometric Theorem of
Poincaré (Birkhoff, 1913, 1925). The original problem, known as the Duffing one, is a 1 degree of freedom system that, besides
the conservative force component, includes dumping and external forcing terms (see details in the web site: http://www.uncwil.edu/people/hermanr/chaos/ted/chaos.html).
The problem considered here is a 2 degree of freedom, autonomous and conservative one, without dumping, and of axisymmetric
potential. The space of permissible motions is scanned for identification of all solutions re-entering after from one to nine
oscillations and the precise families of periodic solutions are computed, including their stability parameter, covering all
cases with periods T corresponding to 4osc/T. Seven sub-domains of the space of solutions were investigated in detail by zooming, an operation that proved the possibility
to advance the accuracy of the approximate general solution to the level permitted by the integration routine. The approximation
of the general solution, although impressive, provides clear evidence of the complexity of the problem and the need to proceed
to larger period families. Nevertheless, it allows prediction of the areas where chaos and order regions in the Poincaré surfaces
of section are to be expected. Examples of such surfaces of sections, as well as of types of closed solutions, are given.
Two peculiar points of the space of solutions were identified as crossing, or source points from which infinite families of
periodic solutions emanate. The morphology and stability of solutions of the problem are studied and discussed. 相似文献
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以当前太阳系动力学中的重要课题以及研究方法进行讨论，并提出一些看法，课题中主要讨论动力学模型，轨道共振，行星环，混沌和长期演化，近地天体运动，Kupiper带，太阳系中的引力理论，以及其他有关问题。 相似文献
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Statistical properties of many-dimensional dynamical systems-stellar systems of different types, are investigated by means of new definition of relative chaos based on the estimation of the Ricci curvature in the direction of the velocity of geodesics. Numerical experiment is performed to calculate the Ricci and scalar curvatures for systems with equal total energy. The results of calculations enable one to obtain schematic classification of stellar systems by increasing degree of chaos. 相似文献
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G. Ciraolo C. Chandre R. Lima M. Vittot M. Pettini 《Celestial Mechanics and Dynamical Astronomy》2004,90(1-2):3-12
We present a technique to control chaos in Hamiltonian systems which are close to integrable. By adding a small and simple
control term to the perturbation, the system becomes more regular than the original one. We apply this technique to a forced pendulum
model and show numerically that the control is able to drastically reduce chaos. 相似文献
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Some general laws of evolution of a system of a large number of gravitating bodies are discussed. If in the initial stage the dynamics of the system is determined by large-scale perturbations of the gravitational potential associated with excitations of a few collective degrees of freedom, then one can assume, by analogy with chaos in the several-body problem (Poincarè chaos), that randomization will occur in the system over several average crossing times. In the next stage of evolution, the energy of collective modes should be transferred by the cascade mechanism to ever smaller scales, down to invididual particles. Numerical experiments and gross-dynamical considerations that could verify this picture and bring out details are discussed. 相似文献
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Takashi Kitamura Soji Ohara Takeharu Konishi Katsufumi Tsuji Michiyuki Chikawa Wasaburo Unno Isao Masaki Kenji Urata Yukihiro Kato 《Astroparticle Physics》1997,6(3-4):279-291
Unexpected chaotic features are found in time series of arrival time intervals of successive air showers with (E > 3 × 1014 eV). Over 99 % of air shower arrival time intervals obey the Poisson distribution law representing stochastic behaviors, but occasionally there are air showers showing real chaotic behaviors as distinguished from both random and colored noises. With two systems of the Kinki university installations, we found 13 cases showing chaotic time series in 3.36 yr with the system-1 and the 1.37 yr with the system-2. Five out of 10 chaotic air showers of the Kinki installation are detected during the same time zone also by the Osaka City university installation which is at 115 km distance from the Kinki one. In a remarkable example of September 19, 1991, the correlation dimension was observed to have dropped from about 4 to the minimum of 1.3 and recovered smoothly in about 38 h. The chaos structure in this case is detected in nearly the same time zone at the Ohya station of the Institute for Cosmic Ray Research, University of Tokyo, which is separated from the Kinki one by 460 km. Formation of chaos structure due to energetic cosmic ray dust particles is suggested. Progress of cosmic ray physics may be expected with the study of air showers marked with chaos. 相似文献
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Rónadh COX Lissa C. F. ONG Masahiko ARAKAWA Kate C. SCHEIDER 《Meteoritics & planetary science》2008,43(12):2027-2048
Abstract— Ice thickness estimates and impactor dynamics indicate that some impacts must breach Europa's ice crust; and outcomes of impact experiments using ice‐over‐water targets range from simple craters to chaos‐like destroyed zones, depending on impact energy and ice competence. First‐order impacts‐into thick ice or at low impact energy‐produce craters. Second‐order impacts punch through the ice, making holes that resemble raft‐free chaos areas. Third‐order impacts‐into thinnest ice or at highest energy‐produce large irregular raft‐filled zones similar to platy chaos. Other evidence for an impact origin for chaos areas comes from the size‐frequency distribution of chaos+craters on Europa, which matches the impact production functions of Ganymede and Callisto; and from small craters around the large chaos area Thera Macula, which decrease in average size and density per unit area as a function of distance from Thera's center. There are no tiny chaos areas and no craters >50 km diameter. This suggests that small impactors never penetrate, whereas large ones (ÜberPenetrators: >2.5 km diameter at average impact velocity) always do. Existence of both craters and chaos areas in the size range 2–40 km diameter points to spatial/temporal variation in crust thickness. But in this size range, craters are progressively outnumbered by chaos areas at larger diameters, suggesting that probability of penetration increases with increasing scale of impact. If chaos areas do represent impact sites, then Europa's surface is older than previously thought. The recalculated resurfacing age is 480 (‐302/+960) Ma: greater than prior estimates, but still very young by solar system standards. 相似文献
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This paper describes the results of studies of dynamical chaos in the problem of the orbital dynamics of asteroids near the 3 : 1 mean-motion resonance with Jupiter. Maximum Lyapunov characteristic exponents (MLCEs) are used as an indicator and a measure of the chaoticity of motion. MLCE values are determined for trajectories calculated by the numerical integration of equations of motion in the planar elliptical restricted three-body problem. The dependence of the MLCE on the problem parameters and on the initial data is analyzed. The inference is made that the domain of chaos in the phase space of the problem considered consists of two components of different nature. The values of the MLCEs observed for one of the components (namely, for the component corresponding to low-eccentricity asteroidal orbits) are compared to the theoretical estimates obtained within the framework of model of the resonance as a perturbed nonlinear pendulum. 相似文献