Effect of normalized plasma frequency on electron phase-space orbits in a free-electron laser

Irregular phase-space orbits of the electrons are harmful to the electron-beam transport quality and hence deteriorate the performance of a free-electron laser （FEL）. In previous literature, it was demonstrated that the irregularity of the electron phase-space orbits could be caused in several ways, such as varying the wiggler amplitude and inducing sidebands. Based on a Hamiltonian model with a set of self-consistent differential equations, it is shown in this paper that the electron- beam normalized plasma frequency functions not only couple the electron motion with the FEL wave, which results in the evolution of the FEL wave field and a possible power saturation at a large beam current, but also cause the irregularity of the electron phase-space orbits when the normalized plasma frequency has a sufficiently large value, even if the initial energy of the electron is equal to the synchronous energy or the FEL wave does not reach power saturation.

Methodology of Wavelets in Relativistic Heavy Ion Collisions in One Dimensional Phase Space (<i>η</i>-Space)

An attempt has been made to apply the wavelet methodology for the study of the results of the chaotic behavior of multiparticle production in relativistic heavy ion collisions. We reviewed the data that describes the collisions of relativistic heavy ion for the case η-space in 1-D phase space of variable. We compared the experimental data and UrQMD data using wavelet coherency. We discussed the results of the comparison.

Study of Wavelet Methodology and Chaotic Behavior of Produced Particles in Different Phase Spaces of Relativistic Heavy Ion Collisions

We applied the wavelet methodology for our earlier published research work of the chaotic behavior so called multiplicity fluctuations of secondary charged particles produced during the nucleus-nucleus (A-A) collisions at an energy of the order of ≈ 409 GeV in a new fashion. We illustrated the wavelet coherency in a relation of chaotic behavior for above said data of secondary charged pions in different phase spaces of collisions such as: η-space, φ-space (in one dimension) and ηφ-space (in two dimensions) respectively. We have shown the changes in the wavelet coherence when there are different values of two parameters “q” and “p”. We discussed our new results for the comparison purpose and findings were in the good agreements.

基于比例导引的空间交会寻的段飞行任务设计

比例导引涉及的参数测量和控制手段简便,常被用作空间拦截的制导算法。基于该制导算法,在相对运动参数测量条件较弱的情况下,对空间交会对接寻的段飞行任务进行了设计。采用C-W制导算法,对寻的段飞行任务的标称轨道进行了设计。推导了基于固定推力发动机的比例导引轨道控制模型,并利用该模型对寻的段轨道进行了控制。通过仿真计算验证了所给出的比例导引模型的有效性。

多种减方差技术在电子辐照加速器屏蔽计算中的组合应用效果评估

减方差技术是辐射防护、核医学、核探井等应用领域中解决深穿透问题的常用方法。当前减方差技术的研究基本基于简单理论几何模型,缺少在实际复杂模型上的讨论,本文以实际应用的电子辐照加速器整体系统为研究的几何模型,以屏蔽后的剂量为计算目标。比较了电子和不同辐照物质相互作用时产生次级光子能量谱和方向谱的差异,并以蒙特卡罗程序MCNP5(Monte Carlo N Particle Transport Code)为平台详细研究对比了几何分裂、源偏倚、指数衰减、分步输运、DXTRAN球和权窗等常见减方差技术在单独使用和不同组合使用下的实际效果,评估了具有实用性减方差技术的选择和组合。结果表明:辐照物质对次级光子的方向谱影响很大,出于建模有效性考虑,几何模型应尽量贴合实际,不能过分简化;分步输运和源偏倚相比于其它常规减方差技术可以更好地降低计算误差,它们和几何分裂、DXTRAN球和指数衰减组合使用时,可以进一步降低计算误差,有效提高结果的可信度;权窗相对于常规减方差技术具有更好的计算效率和客观性,以权窗、分步输运和源偏倚为基础,再组合其他减方差技术,可以很好地解决实际应用中复杂模型的深穿透问题。

欧拉海森堡黑洞的弱宇宙监督

文章计算带电粒子落入欧拉海森堡黑洞时,视界附近的能量-动量关系,验证通常相空间和扩展相空间情况下黑洞的弱宇宙监督假设。文章发现在通常相空间中,极端黑洞和近极端黑洞的弱宇宙监督假设均有效;另一方面,在扩展相空间中,只有极端黑洞的弱宇宙监督假设有效,而对于近极端黑洞其影响参数比较多,无法证明其弱宇宙监督假设是否有效。

高概率宽带相位干涉仪测向解模糊算法

先进作战飞机电子战系统采用宽带相位干涉仪对辐射源进行高精度方位测量。在相位干涉仪测向系统的常规解模糊算法基础之上,提出了一种基于加权投影空间全基线均方差最小的解算方法。理论分析和仿真计算表明,该方法可大幅度提升相位干涉仪测向的解模糊概率,拓宽了机载宽带相位干涉仪的应用条件。

d维RN-AdS黑洞的弱宇宙审查猜想

阐述计算带电粒子被d维RN-AdS黑洞吸入时,视界附近的能量-动量关系,可以验证正常相空间和扩展相空间情况下黑洞的弱宇宙审查猜想是否满足。分析表明,在正常相空间中,极端黑洞和近极端黑洞的弱宇宙审查猜想均满足;另一方面,在扩展相空间中,只有极端黑洞的弱宇宙审查猜想才满足,而对于近极端d维RN-AdS黑洞受参数的影响,无法证明其弱宇宙审查猜想是否能够满足。

The Proof That There Are No Invariabilities of Lorentz Transformations in the Interaction Theories of Micro-Particle Physics

It is proved in this paper that there are at least five situations in the interaction theories of microparticle physics that the Lorentz transformations have no invariabilities. 1) In the formula to calculate transition probabilities in particle physics, the so-called invariability factor of phase space d3p/E is not invariable actually under the Lorentz transformations. Only in one-dimensional motion with uy = uz = 0, it is invariable. 2) The propagation function of spinor field in quantum theory of field has no invariability of Lorentz Transformation actually. What appears in the transformation is the sum of Lorentz factors aμνaλμ ≠ δνλ when ν, λ = 1, 4, rather than aμνaλμ = δνλ. But in the current calculation, we take aμνaλμ = δνλ. The confusion of subscript’s position leads to wrong result. 3) Though the motion equations of quantum fields and the interaction Hamiltonian are unchanged under the Lorentz transformation, the motion equation of perturbation which is used to calculate the transition probability in the interaction representation has no invariability. 4) The interactions between bound state’s particles have no Lorentz invariability. In fact, the principle of relativity has no approximation if it holds. 5) The calculation methods of high order perturbations normalization processes in quantum theory of fields violate the invariability of Lorentz transformation. The conclusions above are effective for strong, weak and electromagnetic interactions and so on. Therefore, the principle of relativity does not hold in the micro-particle’s interactions. On the other hand, the invariability principle of light’s speed is still effective. So the formulas of special relativity still hold, but we should consider them with absolute significances.

相干态在参数量子相空间的两维正态分布

把量子力学与数理统计的正态分布联系起来进行初步的尝试.用数理统计的观点和有序算符内的积分技术研究相干态,指出在依赖一个实参数k的量子化方案中,相干态|z??z|在相空间呈现出以(q,p)为随机变量的两维正态分布,z=(q+ip)/√2.两个随机变量的相关系数为ik.在k=±1的参数相空间中,|z??z|分别表现出P排序(P在Q左)和Q排序的形式(Q在P左),而在k=0的参数相空间中,|z??z|表现出Weyl排序的形式.在P排序和Q排序的情况下,量子算符|z??z||z=(q+ip)/√2的经典对应函数中随机变量(q,p)是关联的,只有在Weyl对应时,随机变量(q,p)是独立的.也就是说,算符的Weyl排序有利于其经典对应的随机变量解脱关联.