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1.
Journal of Experimental and Theoretical Physics - The problem of propagation of a magnetic inhomogeneity in the form of a magnetic vortex near a defect simulated by a crystallite with uniaxial...  相似文献   

2.
The equation and dispersion relation describing the magnetic electron drift vortex mode in a generalized equilibrium are presented. The results are useful for investigating related surface wave problems as well as for identifying the various forms of the magnetic electron drift vortex mode.  相似文献   

3.
It is found from Maxwell's equations that the magnetic field lines are good analogues of relativistic strings. It is shown that the superconducting current in the neutron star's interior causes local rotation of magnetic flux tubes carrying quantized flux.  相似文献   

4.
陈永寿  舒能川  吴开谡 《中国物理 C》2004,28(12):1349-1355
简要地评述天体核过程,着重讨论爆发性氢燃烧过程,并利用最新的反应率实验数据对氢燃烧过程进行了计算.指出从热pp链通过11C的质子辐射俘获反应进入CNO循环的反应流量可以超过3α过程的流量.用18F(p,γ)和(p,α)反应的新反应率计算的18F生成丰度比旧反应率给出的丰度要大1.8倍.对在X射线爆的典型天体物理条件下的快质子(rp)过程的计算表明,“等待核”89Ru和93Pd的β衰变寿命的新实验数据给出的该2核的生成丰度,比旧实验数据给出的值要大4倍.  相似文献   

5.
In the framework of time-dependent two-dimensional Gross-Pitaevskii equation, we investigate the dynamics of vortex formation in rotating dipolar Bose-Einstein condensates in synthetic magnetic field (SMF) and compare with rotating frame (RF) method. The formation of vortices are calculated, considering effects of the rotational frequency, dipole strength, tilting angle and trap ratio. The results we found are that in SMF, the formation of steady state vortices is much slower than that in RF, and it is more difficult to add large angular momentum to the condensates than to do so in RF.  相似文献   

6.
The Review summarizes much of particle physics and cosmology.Using data from previous editions,plus 3,062 new measurements from 721 papers,we list,evaluate,and average measured properties of gauge bosons and the recently discovered Higgs boson,leptons,quarks,mesons,and baryons.We summarize searches for hypothetical particles such as supersymmetric particles,heavy bosons,axions,dark photons,etc.All the particle properties and search limits are listed in Summary Tables.We also give numerous tables,figures,formulae,and reviews of topics such as Higgs Boson Physics,Supersymmetry,Grand Unified Theories,Neutrino Mixing,Dark Energy,Dark Matter,Cosmology,Particle Detectors,Colliders,Probability and Statistics.Among the 117 reviews are many that are new or heavily revised,including new reviews on Pentaquarks and Inflation.  相似文献   

7.
Nuclear reactions involving light nuclei require few-body models to describe the nuclear structure and the reaction mechanism. The production rates for the α+n+n6 He+γ and α+n+n+n6 He+n processes are discussed. Typically only very low relative energies are relevant. For environments with a high density, processes involving more particles could dominate. The use of the adiabatic approach as a method to compute cross sections at very low energies is proposed.  相似文献   

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9.
核天体物理是研究微观世界的核物理与研究宏观世界的天体物理融合形成的交叉学科,其主要研究目标是:宇宙中各种化学元素核合成的过程、时间、物理环境、天体场所及丰度分布;核反应(包括带电粒子、中子、光子及中微子引起的反应、β衰变及电子俘获)如何控制恒星的演化过程和结局。近十多年来获得的大量实验和理论研究使核天体物理研究进入了一个蓬勃发展的新阶段。文章总结了以兰州重离子加速器、北京串列加速器和国家天文台为基础,结合国际合作,在核天体物理研究领域对直接测量、间接测量、衰变测量、质量测量、理论计算、网络计算、天文观测等关键科学问题进行的研究进展。也展望了核天体物理的关键科学问题,这些关键问题包括:(1)在地面实验室、尤其是地下实验室开展天体物理能区重要热核反应截面的直接测量;(2)高能区带电粒子反应截面向天体物理能区的合理外推;(3)恒星平稳核燃烧阶段和爆发性天体事件中关键核反应截面的间接测量;(4)爆发性天体事件中所涉及的大量远离稳定线核素的质量、衰变特性和共振态性质的研究;(5)建立并不断完善核天体物理数据库,发展网络模拟程序,系统研究元素核合成的天体场所、丰度分布;(6)宇宙中铁以上元素的来源之谜。Nuclear astrophysics is an interdisciplinary research field. It composes of nuclear physics, which studies micro phenomena, and astrophysics which studies macroscopic phenomena in our world. The main research goals of nuclear astrophysics are:(1) how, when and where chemical elements are synthesized and what is their final abundance distribution in the universe; (2) how nuclear processes (reactions induced by charged particles, neutrons, photons and neutrinos, beta decays and electron capture processes) determine the evolution and the ultimate fate of stars. At present, nuclear astrophysics has been developed into a new prosperous stage with a huge number of experimental and theoretical progresses. This paper summarized the current progress of nuclear astrophysics in China, in the subfiels of direct and indirect measurement of key reactions, measurement of mass and decay, as well as the theoretical calculation and network simulation. In present paper, the prospects to solve the key scientific nuclear astrophysics problems are represented. These key problems include (1) direct measurement of important reactions at astrophysical energies in the laboratory on the earth surface and in the underground laboratory; (2)extrapolation of cross sections at higher energies for the reactions induced by charged particles; (3) indirect measurement of key reactions in the hydrostatic and explosive nuclear processes; (4) study of the mass, the properties of decay and resonant states for the nuclides far from the stability line in explosive astrophysical events; (5) establish and improve the database for nuclear astrophysics, and develop network simulation codes, and systematically study astrophysical sites and abundance distribution of nucleosynthesis; (6) origin of the elements heavier than iron in the universe.  相似文献   

10.
11.
Russian Physics Journal - Stationary configuration of a rotating electrically charged ideal fluid with self-gravitation is considered within the framework of general relativity. Barotropic equation...  相似文献   

12.
Technical Physics - The effect of the fractality of the cluster interfaces in the normal phase of a copper-oxide high-temperature superconductor YBCO on the magnetic creep has been studied. The...  相似文献   

13.
As the rate of energy release in a double layer with voltage ?V is P ? I?V, a double layer must be treated as a part of a circuit which delivers the current I. As neither double layer nor circuit can be derived from magnetofluid models of a plasma, such models are useless for treating energy transfer by means of double layers. They must be replaced by particle models and circuit theory. A simple circuit is suggested which is applied to the energizing of auroral particles, to solar flares, and to intergalactic double radio sources. Application to the heliospheric current systems leads to the prediction of two double layers on the sun's axis which may give radiations detectable from Earth. Double layers in space should be classified as a new type of celestial object (one example is the double radio sources). It is tentatively suggested that X-ray and ?-ray bursts may be due to exploding double layers (although annihilation is an alternative energy source). A study of how a number of the most used textbooks in astrophysics treat important concepts such as double layers, critical velocity, pinch effects, and circuits is made. It is found that students using these textbooks remain essentially ignorant of even the existence of these concepts, despite the fact that some of them have been well known for half a century (e.g., double layers, Langmuir, 1929; pinch effect, Bennet, 1934).  相似文献   

14.
H. O. U. Fynbo 《Few-Body Systems》2013,54(7-10):843-848
The 3α-reaction is one of the key reactions in nuclear astrophysics. Since it is a three-body reaction direct measurement is impossible, and therefore the reaction rate must be estimated theoretically. In this contribution I will discuss uncertainties in this reaction rate both at very low temperatures, temperatures typical for Helium burning in red giant stars, and for very high temperatures.  相似文献   

15.
An explanation for the observed scale invariants in the universe is presented. Force-free magnetic vortex filaments are proposed to play a crucial role in the formation of superclusters, clusters, galaxies, and stars by initiating gravitational compression. The critical velocities involved in vortex formation are shown to explain the observed constant orbital velocities of clusters, galaxies, and stars. A second scale invariant nr = C where n is particle density and r is average distance between objects, is also noted here and explained by our model. The model predicts a maximum size for magnetic vortices, which is comparable to the dimensions of the observable universe and a density for such vortices which is close to that actually observed, eliminating any theoretical need for missing mass. On this basis, we present an alternative cosmology to that of the "Big Bang," one which provides a much better fit to recent observations of large-scale structure and motion. The model suggests scale invariants between microscopic and cosmological scales, leading to the derivation of a simple analytical expression for the fundamental constants G, mp/me, and e2/hc. We conclude that these expressions indicate the existence of vortex phenomena on the particle level.  相似文献   

16.
Summary High-energy astrophysics is critically discussed, covering supernova explosions, single and binary neutron stars and active galactic nuclei as well as some acceleration mechanisms like homopolar induction (in a rotating magnetized conductor), radial boosting by strong magnetic waves, electric discharges in clumped accretion flows and the grindstone effect of plasma falling on a rotating magnet. It is not clear whether the highest particle energies in the Galaxy are achieved in single-step or in coherent multiple-step accelerations.
Riassunto Si discute criticamente l'astrofisica delle alte energie, includendo le esplosioni di supernovae, le stelle di neutroni singole e binarie e i nuclei galattici attivi oltre ad alcuni meccanismi di accelerazione come l'induzione omopolare (in un conduttore magnetizzato ruotante), boosting radiale mediante onde elettromagnetiche forti, scariche elettriche di flussi di accrescimento raggruppato e l'effetto a mola del plasma in caduta su un magnete ruotante. Non è chiaro se le energie piú alte delle particelle nella Galassia si raggiungono in accelerazioni ad un singolo passo o a molti passi coerenti.

Резюме Критически обсуждаются вопросы астрофизики высоких энергий, включающие: взрывы сверхновых, отдельные и бинарные нейтронные звезды, ядра активных галактик, а также механизмы ускорения, подобные гомополярной индукции (при вращении намагниченного проводника), радиальное усиление благодаря сильным магнитным волнам, электрические разряды в аккретирующих потоках и эффекты ?точильного камня? в плазме, падающей на вращающийся магнит. Отмечается, что не ясно, как возникают в Галактике частицы сверхвысоких энергий: за счет одноступенчатого механизма ускорения или в результате когерентных многостуненчатых ускорений.
  相似文献   

17.
裘丛欣  徐仁新 《中国物理快报》2006,23(12):3205-3207
Colour confinement is only a supposition, which has not yet been proven in QCD. Here we propose that macroscopic quark-gluon plasma in astrophysics could hardly maintain colourless because of causality. It is expected that the existence of chromatic strange quark stars as well as chromatic strangelets preserved from the QCD phase transition in the early Universe could be unavoidable if their colourless correspondents do exist.  相似文献   

18.
The indirect method of determining astrophysical nuclear reaction rates is discussed. The overall normalization of the astrophysical S-factor for such reactions may be determined from one quantity, the asymptotic normalization coefficient of the overlap function of the bound state wave functions for the initial and final channels. These coefficients can be found also from peripheral transfer reactions whose amplitudes are determined by the same overlap function as the amplitudes of the corresponding astrophysical radiative capture processes. The experimental test of this approach and the last results of S17 measurements are presented.  相似文献   

19.
Three-body continuum problems are investigated for light nuclei of astrophysical relevance. We focus on three-body decays of resonances or recombination via resonances or the continuum background. The concepts of widths, decay mechanisms and dynamic evolution are discussed. We also discuss results for the triple ?? decay in connection with 2+ resonances and density and temperature dependence rates of recombination into light nuclei from ??-particles and neutrons.  相似文献   

20.
柳艳  李化南  胡勇  杜安 《计算物理》2013,30(6):915-920
选取具有尺寸限制的点接触结构作为研究对象,采用Thiele方程对模型中磁涡旋在自旋极化电流作用下的动力学行为进行计算.计算表明磁涡旋可以在一定的电流密度范围内稳定旋转,该稳定旋转可以存在的电流密度范围与点接触区的大小和纳米点的尺寸有关.当磁涡旋核作稳态旋转时,其所处的轨道半径以及旋转频率都随电流密度的增加而增加,旋转频率可调节的范围随点接触尺寸的增加快速减小.  相似文献   

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