Theory of Shear Alfven Vortex in Current-Carrying Plasma Plasma

Nonlinear shear Alfven waves in low P, current-carrying magnetized plasma are studied.Sets of nonlinear equations describing the shear Alfven waves are derived and corresponding dipolar vortex solutions are given for both regions of P, 0<β< m_e/m_i and m_e/m_i<<β<<1, respectively. Result shows that the equilibrium plasma current has remarkable effect on the behaviour of vortex motion. For the 0<β<< m_e/m_i case the current adds a low speed vortex propagating region in the opposite current direction, while for the < m_e/m_i<<β<<1 case the current reduces the region of vortex propagating speed by cutting a low speed region. The implication of this effect is discussed.     

阿尔芬高斯波包演化为阿尔芬孤波的条件及阿尔芬波的调制不稳定性判据

通过计算阿尔芬孤波的运动常数C1，发现消零孤波（vanishing soliton）均满足C1≤0，结合其他研究者关于阿尔芬波调制不稳定性的定性结论，提出阿尔芬波包演化为孤波的条件为C1≤0.数值计算结果支持了这个猜测.同时计算结果还表明,最终演化成的孤波数目既不完全依赖于积分常数C0，也不完全依赖于C1 .文献［1］和［2］所得的结论源于演化时间太短.通过与其他文献比较，发现C1≤0还可以作为阿尔芬波的调制不稳定性判据. 关键词： 阿尔芬波 derivative nonlinear Schrdinger方程 调制不稳定性判据 孤立波 高斯波包     

Plasma physics in Latin America

The status of plasma physics in Latin America is reviewed. The review surveys the history and present situation of the regional activities in high-temperature plasma research, plasma astrophysics, and technological applications of plasma physics. In particular, it presents data on the trends of evolution of scientific staff, annual operating budget, and publication rate for the major Latin American plasma groups during the decade 1983-1992. On this basis, the prospects for further growth and the potential for regional contribution to the mainstream of international plasma research and development are discussed     

对物理实验课程兴趣的分析和研究

讨论了在校大学生对物理实验课程学习的现状,以及应采取什么方法去引导和激发学生的学习兴趣。     

Fine Structure of the Local Alfven Resonances in Cold Plasma Placed in Bumpy Magnetic Field

Unlike in the case of an axial magnetic field, in which each mode of electromagnetic wave excited by an external source propagates independently, ripples in a bumpy magnetic field cause the wave to propagate as a wave envelope that contains also satellite harmonics in addition to the main harmonic. The influence of this multimodity on the distribution of electromagnetic waves within the local Alfven resonance regions is studied and compared for the following three cases. In the first case, Alfven resonance takes place for a main harmonic of the wave. In the second case, Alfven resonance occurs in the same region for two main harmonics which are coupled due to the plasma periodic axial inhomogeneity. Alfven resonance for a satellite harmonic is considered in the third case.     

Plasma physics issues in gas discharge laser development

An account is given of the interplay between partially ionized plasma physics and the development of gas discharge lasers. Gas discharge excitation has provided a wide array of laser devices extending from the soft X-ray region to the far infrared. The scaling of gas discharge lasers in power and energy also covers many orders of magnitude. The particular features of three regimes are discussed: short wavelength lasers (deep UV to soft X-ray), visible and near UV lasers, and infrared molecule gas lasers. The current status (fall, 1990) of these areas is reviewed and an assessment is made of future research topics that are perceived to be important     

Glass physics: from fundamentals to applications

The European Physical Journal E -     

High-p t and jet physics from RHIC to LHC

The observation of the strong suppression of high-p t hadrons in heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) at BNL has motivated a large experimental program using hard probes to characterize the deconfined medium created. However, what can be denoted as “leading particle” physics accessible at RHIC presents some limitations which motivate at higher energy the study of much more penetrating objects: jets. The gain in center-of-mass energy expected at the Large Hadron Collider (LHC) at CERN will definitively improve our understanding on how the energy is lost in the system, opening a major new window of study: the physics of jets on an event-by-event basis. We will concentrate on the expected performance for jet reconstruction in ALICE using the EMCal calorimeter. (for the ALICE Collaboration) The text was submitted by the author in English.     

Nature of monster sawteeth and their relationship to Alfven instabilities in tokamaks

A correlation is explored between the presence of energetic particle modes (EPM) and long-period sawtooth oscillations in tokamak plasmas heated by rf waves. The eventual crash of these sawteeth is explained in terms of the loss of the stabilizing fast particles due to the EPM. The absence of long-period sawteeth in high q(a) discharges is explained in terms of ion loss due to toroidal Alfven eigenmodes.     

物理学新技术与生命科学前沿研究

物理学新技术对现代生命科学取得的巨大成就发挥了极其重要的作用；生命科学和医学的需要又促进了物理新技术和仪器的发展。本文介绍了在生命科学一些前沿研究领域中应用物理学新技术取得的成果，并展望了21世纪的发展前景，包括：单分子动力学、结构生物学、纳米技术和生物技术、分子细胞信息学、脑科学和神经信息学。     

Prebiological evolution and the physics of the origin of life

The basic tenet of the heterotrophic theory of the origin of life is that the maintenance and reproduction of the first living systems depended primarily on prebiotically synthesized organic molecules. It is unlikely that any single mechanism can account for the wide range of organic compounds that may have accumulated on the primitive Earth, suggesting that the prebiotic soup was formed by contributions from endogenous syntheses in reducing environments, metal sulphide-mediated synthesis in deep-sea vents, and exogenous sources such as comets, meteorites and interplanetary dust. The wide range of experimental conditions under which amino acids and nucleobases can be synthesized suggests that the abiotic syntheses of these monomers did not take place under a narrow range defined by highly selective reaction conditions, but rather under a wide variety of settings. The robustness of this type of chemistry is supported by the occurrence of most of these biochemical compounds in the Murchison meteorite. These results lend strong credence to the hypothesis that the emergence of life was the outcome of a long, but not necessarily slow, evolutionary processes. The origin of life may be best understood in terms of the dynamics and evolution of sets of chemical replicating entities. Whether such entities were enclosed within membranes is not yet clear, but given the prebiotic availability of amphiphilic compounds this may have well been the case. This scheme is not at odds with the theoretical models of self-organized emerging systems, but what is known of biology suggest that the essential traits of living systems could have not emerged in the absence of genetic material able to store, express and, upon replication, transmit to its progeny information capable of undergoing evolutionary change. How such genetic polymer first evolved is a central issue in origin-of-life studies.     

近代物理实验网络课件的制作

以当代西方教育心理学的最新理论——建构主义和课件制作的离散化理论——积件思想为理论指导，比较国内和国外、传统与现今的近代物理实验模式．以设计制作《近代物理实验网络课件》中《扫描隧道显微镜STM》网络课件为例，不是用课件代替实验课，而是通过课件调动学生学习的主观能动性，充分利用互联网拓宽学生的知识面。     

Contribution from the Earth＇s Bow Shock to Region 1 Current under Low Alfven Mach Numbers

Using global MHD simulations of the solar wind-magnetosphere-ionosphere system, we investigate the dependence of the contribution from the Earth＇s bow shock （I1bs） to ionospheric region 1 field aligned current （FAC） （I1）. R is found that Ilbs increases with increasing southward interplanetary magnetic field （IMF） strength Bs, if the AIfven Mach number MA of the solar wind exceeds 2, a similar result as obtained by previous authors. However, if MA becomes close to or falls below 2, I1ba will decrease with Bs in both magnitude and percentage （i.e., I1bs/I1） because of the resultant reduction of the bow shock strength. Both the surface current density Jbs at the nose of the bow shock and the total bow shock current Ibs share nearly the same relationship with MA, and vary non-monotonically with MA or Bs. The maximum point is found to be located at MA = 2.7. Three conclusions are then made as follows： （1） The surface current density at the nose, which is much easier to be evaluated, may be used to largely describe the behaviour of the bow shock instead of the total bow shock current. （2） The peak of the total bow shock current is reached at about MA = 2.7 when only Bs is adjusted. （3） The non-monotonic variation of the bow shock current with MA causes a similar variation of its contribution to region 1 FAC. The turning point [or such contribution is found to be nearly MA = 2. The implication of these conclusions to the saturation of the ionospheric transpolar potential is briefly discussed.     

The physics and biology of fluorescence microscopy in the life sciences

The last decade has seen a renaissance in the use of fluorescence microscopy in biology. This development was fuelled by the discovery of autofluorescent proteins that, through simple genetic conjugation to virtually any protein of interest, allowed their investigation of living cells. Importantly, this also prompted the introduction of advanced fluorescence microscopy techniques of ever increasing sophistication that exploit the possibilities of this new labelling technique. The microscope became an analytical instrument, images became rich sources of quantitative information, and we obtained an unprecedented insight into the working of the molecular machines that operate in living cells. This new field is positioned at the interface between biology and physics. This review will provide an historic overview of this process, describing some of the most exciting developments, and mainly focusing on one of the most informative imaging techniques for the elucidation of the chemistry of life; Förster Resonance Energy Transfer microscopy.     

Low- x QCD physics from RHIC and HERA to the LHC

We present a summary of the physics of gluon saturation and non-linear QCD evolution at small values of the parton momentum fraction x in the proton and nucleus in the context of recent experimental results at HERA and RHIC. The rich physics potential of low-x studies at the LHC, especially in the forward region, is discussed and some benchmark measurements in pp, pA and AA collisions are introduced.     

Black hole bombs and explosions: from astrophysics to particle physics

Black holes are the elementary particles of gravity, the final state of sufficiently massive stars and of energetic collisions. With a 40-year long history, black hole physics is a fully-blossomed field which promises to embrace several branches of theoretical physics. Here I review the main developments in highly dynamical black holes with an emphasis on high energy black hole collisions and probes of particle physics via superradiance. This write-up, rather than being a collection of well known results, is intended to highlight open issues and the most intriguing results.     

"进展的物理"对物理教育的挑战

与我国的情形相类似，英国16岁以上学生选学物理的人数逐年下降．“进展的物理”正是英国物理学会(the Institute of Physics)为吸引更多16岁以上学生学习物理而开发的当代物理课程．文章介绍了这一高中物理课程改革的时代背景和基本理念、全新的课程内容和结构、新颖的学习方式和评价模式，试题的形式和例子，对我国正在进行的中学及大学物理课程改革有一定的参考借鉴作用．     

将近代物理内容加入"大平台"普通物理实验

介绍了将近代物理内容加入“大平台”普通物理实验的具体情况.