分形和混沌理论在太阳物理学中的应用

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。     

分形和混沌理论在太阳物理学中的应用

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。     

分形和混沌理论在天体物理中的应用

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。     

分形和混沌理论在天体物理中的应用

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）。     

太阳耀斑区磁场和电流研究的一些新进展

在太阳耀斑区磁场和电流研究方面，文中将着重介绍太阳横向磁场方位的确定，太阳活动区磁场的非热性表示、太阳耀斑前后的活动区磁场变化、以及耀斑核块与活动区纵向电流密度极大点位置的关系等几个重要问题的研究现状。     

太阳耀斑的分类

太阳耀斑分类工作的进展反映了太阳耀斑观测研究与理论研究的进展。本文首先综述耀斑的分类，对近年提出的种种分类作评述，讨论这些分类的观测基础。然后，基于最近两个太阳周的观测工作，提出一种新的多能段太阳耀斑分类方法。按照耀斑在光学，Ｘ射线以及射电波段的观测表象，把耀斑较完整地分为８类。     

太阳质子耀斑和江淮大水的关系

１９９１年５月－６月期间的日面上强质子耀斑的连续爆发,被认为是１９９１年中国江淮特大洪水的重要天文因素。太阳质子耀斑触发和加剧了极涡的冷空气南下,低空西南急流的东移和西太平洋副热带高压的西伸,北抬过程。由于冷暖湿气流在江淮地区频繁地相遇,因此形成了多次暴雨和特大暴雨过程,从而诱发了１９９１年初夏中国江淮流域的特大洪水。     

地球自转变化中的太阳物理效应

对太阳活动和太阳风影响地球自转的研究现状作了评述。首先了地球自转变化的表示和测定方法，引起地球自转变化的各种扰动源以及自转长期变化中的潮汐效应和非潮汐效应。然后对地球自转变化中的太阳活动周期调制，太阳耀斑可能引起地球自转突然减速以及太阳风能否影响地球自转等问题的国内外研究现状和结果、分析作了谰论性阐述，最后作了简要总结。     

太阳物理中磁螺度研究进展

简要回顾了螺度引入太阳磁场研究中的历史过程，从物理角度讨论了相对磁螺度这个新的可观测量，并指出其在理论和观测中存在的问题；着重介绍了磁螺度在太阳大气中的分配问题；探讨了磁螺度和电流螺度的差别与联系、螺度半球手征性；列举介绍了磁螺度和其他太阳活动的联系，尤其是太阳爆发事件中的磁螺度问题；指出磁螺度理论中几个还没有解决的问题及今后可能取得进展的方向。     

Chaos and elliptical galaxies

Recent results on chaos in triaxial galaxy models are reviewed. Central mass concentrations like those observed in early-type galaxies - either stellar cusps, or massive black holes — render most of the box orbits in a triaxial potential stochastic. Typical Liapunov times are 3–5 crossing times, and ensembles of stochastic orbits undergo mixing on timescales that are roughly an order of magnitude longer. The replacement of the regular orbits by stochastic orbits reduces the freedom to construct self-consistent equilibria, and strong triaxiality can be ruled out for galaxies with sufficiently high central mass concentrations.     

Chaos in the solar system

We have accumulated thousands of orbits of test particles in the Solar System from the asteroid belt to beyond the orbit of Neptune. We find that the time for an orbit to make a close encounter with a perturbing planet, T _c ,is a function of the Lyapunov time, T _ty .The relation is log (T _c /T _o )= a + b log (T _ly T _o )where T _o is a fiducial period which we have taken as the period of the principal perturber or the period of the asteroid. There are exceptions to this rule interior to the 2/3 resonance with Jupiter. There, at least in the restricted problem, for sufficiently small Jupiter mass, orbits may have a positive Lyapunov exponent and still be blocked from having a close approach to Jupiter by a zero velocity curve. Of more serious concern is whether the relation holds for purely secular resonances, and if it does, how to choose T _o .This is the case of interest for the planets in the solar system.     

Fractal Dimensions as Chaos Indicators

The correlation dimension D ₂ is used to develop a method of classification for phase space orbits. D ₂ depends only on the mutual distances of the orbits points, therefore the time development of the orbit is reflected in the time development of the correlation dimension approximants. It is shown, that this technique allows to investigate the dynamical properties of a phase space orbit, a classification of chaotic and regular orbits and a detection of sticky orbits.     

Sixty Years in Solar Physics

I recount my career in solar physics beginning at Ondřejov Observatory in 1948 and ending with my ∼30 year stay at the Laboratory of Space Research in Utrecht.     

Solar Activity and Classical Physics

1 INTRODUCTION The Sun is close enough to observe in some detail, and it shows that a star is more than the traditional stable self-gravitating thermonuclear body established half a celltury ago. For the fact is that out of sight beneath the visible surface the outward flow of heat from the thermonuclear core drives hydrodynamics that generates magnetic fields. It is the complicated dynamics of those magnetic fields that produces the modern mysteries of the active Sun. The…     

The 11-Year Magnetic Solar Cycle: Chaos Control Due to Jupiter

Solar System Research - The observed magnetic field of the Sun is believed to originate from a “dynamo-effect” in its convective surface layer. However, there is no natural 11-year...