随机边界对相对论气体玻色-爱因斯坦凝聚临界温度的影响

研究了随机边界对立方箱中相对论气体玻色-爱因斯坦凝聚临界温度的影响.在均匀分布、双模分布和高斯分布情况下,分别计算了临界温度与固定箱中的气体临界温度的比值,发现随机边界降低了系统的临界温度.相对于极端相对论情况,非相对论极限下的临界温度更低.     

强磁场中超冷费米气体的相对论效应

由单粒子的弱相对论能谱及泊松公式,导出强磁场中费米气体的热力学势函数.在此基础上,运用热力学关系求解低温条件下系统的统计特征量的解析式,分析相对论效应对统计性质的影响机理.研究表明,磁场愈强,相对论效应愈明显.相对论效应引发的单调项与相应的振荡项的振幅相比,对总能,单调项远大于振幅;对化学势及磁矩,单调项与振幅几乎同一量级. 关键词： 强磁场 费米气体 相对论效应     

强磁场中相互作用费米气体的相对论稳定性

由单粒子的弱相互作用能谱及泊松公式,导出了强磁场中相互作用费米气体的相对论热力学势函数,求解了系统力学稳定性的判别式,分析了相互作用、磁场及相对论效应对系统稳定性的影响机理.结果表明,强磁场中弱相互作用费米气体的力学稳定性会受到弱相互作用的影响,强磁场对这种影响具有调节作用,而相对论效应对相互作用的影响基本没有调节作用.     

光子与相对论麦克斯韦分布电子散射的能谱角度谱研究

光子与相对论麦克斯韦分布电子散射的描述及能谱角度谱计算非常复杂且费时.本文提出了一种光子与相对论麦克斯韦速度分布电子散射的蒙特卡罗(MC)模拟方法,该方法能够细致模拟高温等离子体中任意能量光子与任意温度电子的Compton和逆Compton散射问题.对于散射后光子的能谱和角度谱参数,可以根据电子温度抽样若干不同状态的电子,分别模拟其与光子发生散射,可以得到各次散射后的光子能量和偏转角度,取统计平均后的结果即可获得该光子与该温度电子散射的能谱和角度谱分布.根据该方法编写了光子与相对论电子散射MC模拟程序,开展了高温全电离等离子体中光子与相对论电子散射的能谱角度谱计算和分析,分析结果显示:热运动电子将展宽出射光子能谱,且低能光子与高温电子散射后的蓝移现象明显;出射光子的角度谱很复杂,其决定于入射光子能量、出射光子能量及电子温度.基于该方法计算并以数表形式给出的光子-相对论电子散射能谱角度谱数据,可以供辐射输运数值模拟程序使用.     

磁场中非广延相对论费米系统的统计性质

基于广义外势中的非广延统计理论,运用理论解析与数值模拟方法,研究磁场中非广延极端相对论费米气体的热力学性质,给出总能、热容量、化学势的解析式,分析非广延参数、极端相对论效应、磁场及温度对系统热力学性质的影响机理.研究显示,非广延参数不仅对热力学性质有直接的影响,而且也影响着磁场的物理效应. 随温度的升高,非广延参数及磁场对热力学性质的影响均被放大.极端相对论效应对化学势及热容量有特别显著的影响.     

磁场中非广延相对论费米系统的稳定性

基于磁场中的非广延统计理论,运用理论解析与数值模拟方法,研究磁场中非广延极端相对论费米气体的力学稳定性,给出高温与低温下稳定性条件的解析式,分析非广延参数、极端相对论效应、磁场及温度对系统稳定性的影响机理.     

相对论条件下的三体衰变能量分布

分析了在初动量为零时的等质量三体衰变问题.借助Dalitz图,研究衰变后能量在3个碎片中的分配关系,以及在Dalitz图中的形状.分析了在Newton经典力学、极端相对论和非极端相对论情形下的Dalitz图.在数学上分析图像差异,讨论其根源,并介绍其应用.     

相对论条件下的麦克斯韦分布

本文自玻耳兹曼分布入手，对相对论粒子的麦克斯韦分布作了若干探讨，并由此过渡到非相对论与极端相对论情形．     

在极端相对论性原子核碰撞中奇异粒子的演化

在本文中我们用相对论流体力学方程描述了一个膨胀的夸克-胶子等离子体的演化.在此基础上考虑了相变和相变引起的温度效应后,用弛豫方程计算了不同初始温度的奇异粒子的时空分布以及总的奇异粒子数随时间的演化规律,分判定在极端相对论原子核碰撞中是否产生了夸克物质提供了一种理论依据.     

强磁场中相互作用费米气体的相对论稳定性

由单粒子的弱相互作用能谱及泊松公式,导出了强磁场中相互作用费米气体的相对论热力学势函数,求解了系统力学稳定性的判别式,分析了相互作用、磁场及相对论效应对系统稳定性的影响机理。结果表明,强磁场中弱相互作用费米气体的力学稳定性会受到弱相互作用的影响,强磁场对这种影响具有调节作用,而相对论效应对相互作用的影响基本没有调节作用。     

Cold neutral plasma in a quantizing magnetic field

The chemical potential of a relativistic and an ultrarelativistic electron gas and the energy of an ultrarelativistic electron gas at T = 0 are expressed analytically as functions of the magnetic field. The possible application of these expressions to the investigation of super-compressed matter in the presence of superstrong magnetic fields is discussed.     

Fragmentation of target spectators in ultrarelativistic heavy ion collisions

We demonstrate that the assumption that target spectators fragment isotropically in a gently moving coordinate system is in agreement with pseudorapidity distributions, measured in central ultrarelativistic heavy ion collisions of projectile energy from 14.5A GeV to 200A GeV. Target spectator remnants might be excluded from measurement by introducing a low energy cutoff for the accepted particles at approximately 200 MeV. An approximate scaling is presented for the pseudorapidity distribution of the target spectator fragments. Theoretical tools used for studying intermediate energy heavy ion collisions seem to be applicable in describing target spectator fragmentation in ultrarelativistic heavy ion collisions.     

Angular distribution of transient radiation from an ultrarelativistic particle in a magnetic field

It is shown that a magnetic field acting on an ultrarelativistic charged particle escaping from a conductor changes the intensity of transient radiation. The angular and frequency distribution of transient radiation in the magnetic field is determined. The possibility of determining the energy of the ultrarelativistic particle from the change in the azimuthal asymmetry of transient radiation emitted by this particle in the magnetic field is discussed.     

Tidal dynamics of relativistic flows near black holes

We point out novel consequences of general relativity involving tidal dynamics of ultrarelativistic relative motion. Specifically, we use the generalized Jacobi equation and its extension to study the force‐free dynamics of relativistic flows near a massive rotating source. We show that along the rotation axis of the gravitational source, relativistic tidal effects strongly decelerate an initially ultrarelativistic flow with respect to the ambient medium, contrary to Newtonian expectations. Moreover, an initially ultrarelativistic flow perpendicular to the axis of rotation is strongly accelerated by the relativistic tidal forces. The astrophysical implications of these results for jets and ultrahigh energy cosmic rays are briefly mentioned.     

Relativistic laser-matter interaction and relativistic laboratory astrophysics

The paper is devoted to the prospects of using the laser radiation interaction with plasmas in the laboratory relativistic astrophysics context. We discuss the dimensionless parameters characterizing the processes in the laser and astrophysical plasmas and emphisize a similarity between the laser and astrophysical plasmas in the ultrarelativistic energy limit. In particular, we address basic mechanisms of the charged particle acceleration, the collisionless shock wave and magnetic reconnection and vortex dynamics properties relevant to the problem of ultrarelativistic particle acceleration.     

The external field effect on transient radiation of an ultrarelativistic particle

An external field determining the law of particle motion was shown to change the intensity of transient radiation in the ultrarelativistic case. The angular and frequency distribution of transient radiation in an external field was obtained. The possibility of determining the energy of an ultrarelativistic particle from the measured azimuthal asymmetry of particle transient radiation in an external field was discussed.     

Ultrarelativistic black-hole encounters

A method is given for investigating the ultrarelativistic encounter of two black holes which complements the usual low-speed approximation. It depends on the fact that the ultrarelativistic limit of a moving Schwarzschild black hole is a certain plane-fronted impulsive gravitational wave. This enables linearized theory on a curved background to be used. The solution is obtained, with the help of generalized function techniques, to the first order in the background energy, and the radiation pattern at conformal null infinity is examined. The whole approach has a strong connection with the theory of twistors.     

Quenching of hadron spectra due to the collisional energy loss of partons in the quark-gluon plasma

We estimate the energy loss distribution and investigate the quenching of hadron spectra in ultrarelativistic heavy-ion collisions due to the collisional energy loss of energetic partons from hard parton collisions in the initial stage.     

On the problem of hard jet recognition in heavy ion collisions

The intrinsic structure of “true” jets from hard parton-parton scattering and “false” jets from the transverse energy flux in high energy nucleus-nucleus collisions is analyzed. The predicted significant distinction allows us to develop more effective algorithms of hard jet extraction from a “thermal” background in ultrarelativistic heavy ion collisions.     

Conditions for the appearance of gravitational ultrarelativistic spin-orbital interaction

A qualitative analysis of the energy and momentum integrals for the Mathisson-Papapetrou equations in a Schwarzschild field is employed to determine the conditions under which all solutions of the exact Mathisson-Papapetrou equations corresponding to fixed initial coordinate and velocity values differ significantly from the solution of the abbreviated equations normally used for the same initial data. Numerical computer calculations provide additional indication of a difference in the world lines of the exact Mathisson-Papapetrou equations from solutions of the geodesic equations at ultrarelativistic velocity values. For high energy particles entering into the composition of cosmic rays one can expect appearance of gravitational ultrarelativistic spin-orbital interaction upon motion of such particles in the field of a neutron star.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 8–12, October, 1985.