共查询到20条相似文献,搜索用时 15 毫秒
1.
Zhen-Yan Lu Jian-Feng Xu Xin-Jian Wen Guang-Xiong Peng Marco Ruggieri 《中国物理C(英文版)》2022,46(6):064104-064104-10
The magnetic field and density behaviors of various thermodynamic quantities of strange quark matter under compact star conditions are investigated in the framework of the thermodynamically self-consistent quasiparticle model. For individual species, a larger number density \begin{document}$ n_i $\end{document} ![]()
![]()
leads to a larger magnetic field strength threshold that aligns all particles parallel or antiparallel to the magnetic field. Accordingly, in contrast to the finite baryon density effect which reduces the spin polarization of magnetized strange quark matter, the magnetic field effect leads to an enhancement of it. We also compute the sound velocity as a function of the baryon density and find the sound velocity shows an obvious oscillation with increasing density. Except for the oscillation, the sound velocity grows with increasing density, similar to the zero-magnetic field case, and approaches the conformal limit \begin{document}$ V_s^2=1/3 $\end{document} ![]()
![]()
at high densities from below. 相似文献
2.
Photons propagating in strong magnetic fields are subject to a phenomenon called the “vacuum birefringence” where refractive indices of two physical modes both deviate from unity and are different from each other. We compute the vacuum polarization tensor of a photon in a static and homogeneous magnetic field by utilizing Schwinger’s proper-time method, and obtain a series representation as a result of double integrals analytically performed with respect to proper-time variables. The outcome is expressed in terms of an infinite sum of known functions which is plausibly interpreted as summation over all the Landau levels of fermions. Each contribution from infinitely many Landau levels yields a kinematical condition above which the contribution has an imaginary part. This indicates decay of a sufficiently energetic photon into a fermion–antifermion pair with corresponding Landau level indices. Since we do not resort to any approximation, our result is applicable to the calculation of refractive indices in the whole kinematical region of a photon momentum and in any magnitude of the external magnetic field. 相似文献
3.
The damping decrement of Landau damping and the effect of thermal velocity on the frequency spectrum of a propagating wave in a bounded plasma column are investigated.The magnetized plasma column partially filling a cylindrical metallic tube is considered to be collisionless and non-degenerate.The Landau damping is due to the thermal motion of charge carriers and appears whenever the phase velocity of the plasma waves exceeds the thermal velocity of carriers.The analysis is based on a self-consistent kinetic theory and the solutions of the wave equation in a cylindrical plasma waveguide are presented using Vlasov and Maxwell equations.The hybrid mode dispersion equation for the cylindrical plasma waveguide is obtained through the application of appropriate boundary conditions to the plasma-vacuum interface.The dependence of Landau damping on plasma parameters and the effects of the metallic tube boundary on the dispersion characteristics of plasma and waveguide modes are investigated in detail through numerical calculations. 相似文献
4.
In this Letter the evolution of a single photon and collective effect of a photon system in background plasma waves are uniformly described in the framework of photon dynamics. In a small-amplitude plasma wave the modulation of photon dynamical behavior by the plasma wave can be treated as perturbation, and photon acceleration effect and photon Landau damping are investigated in linear theory. In an arbitrary-amplitude plasma wave, photon evolution trajectories in phase space are obtained by solving dynamical equations, and photon trapping effect and motion equations in the given plasma wave are also discussed. 相似文献
5.
6.
The photon-scattering process γe ± → γe ± is considered in strongly magnetized matter at arbitrary values of temperature and an arbitrary chemical potential. Simple expressions for the absorption coefficients in a strongly magnetized plasma are obtained in two limiting cases, that of a rarefied chargesymmetric plasma and that of a degenerate plasma. Astrophysical applications of the results obtained here are discussed. 相似文献
7.
The variation of electron temperature and plasma density in a magnetized N2 plasma is studied experimentally in presence of a grid placed at the middle of the system. Plasma leaks through the negatively
biased grid from the source region into the diffused region. It is observed that the electron temperature increases with the
magnetic field in the diffused region whereas it decreases in the source region of the system for a constant grid biasing
voltage. Also, investigation is done to see the change of electron temperature with grid biasing voltage for a constant magnetic
field. This is accompanied by the study of the variation of sheath structure across the grid for different magnetic field
and grid biasing voltage as well. It reveals that with increasing magnetic field and negative grid biasing voltage, the sheath
thickness expands. 相似文献
8.
T. Abbaszadeh H. Zahed S. Salkhi Khasraghi M.S. Sekhavat 《Current Applied Physics》2013,13(9):1933-1942
Dust ion-acoustic waves propagation in the magnetized dusty plasma including ions, electrons and dust particulates are studied by using kinetic equation. For unbounded and collisionless plasma and in the presence of uniform external magnetic field B0, electrons and ions with Lorentzian distribution function and dust particles with Maxwellian one are considered. Calculating dielectric tensor through the Vlasov equation solution, in the parallel propagation, dispersion relation is derived and suprathermal particle effects on the Landau damping is studied. It is shown that the Landau damping effect vanishes for parallel propagation. 相似文献
9.
Influence of arbitrary outside magnetic field on self-focusing of short intense laser pulse propagating in underdense and magnetized cold plasma has been studied in this paper. The outside magnetic field is set in the plane that includes y- and z-axis, and the angle between y-axis and the outside magnetic field is to be used. Results show that there is different effect on self-focusing corresponding to different angle and intensity, the larger this angle, the weaker the effect of self-focusing. The strengthening of outside magnetic field enhances the relevant effect of self-focusing. 相似文献
10.
Based on equations for the evolution of the polarization density matrix for laser emission, we have shown that when a laser
with an anisotropic cavity is turned on in a magnetic field higher than some critical value, we will observe a new optical
effect: pulsations between the polarized and completely unpolarized states of the laser emission. In a magnetic field much
higher than the critical value, practically complete suppression of polarization occurs, which may serve as a method for obtaining
unpolarized laser emission.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 134–142, January–February, 2008. 相似文献
11.
A kinetic formulation is developed to investigate low‐frequency dust ion acoustic waves (DIAWs) and dust acoustic waves (DAWs) as well as numerically for a four‐component, collisionless, unmagnetized dusty plasma, using the linearized Vlasov–Poisson model for species obeying the Maxwellian distribution. In particular, the dynamics of low‐frequency DIAWs is investigated by considering two cases. In the first case, ions and positive dust particles are assumed to be dynamically adiabatic while the negative dust particles are static in the background. In second case, the ions are taken adiabatic, while both positive and negative dust particles are static in the background. For DAWs, the ions are assumed to be isothermal, while both positive and negative dust species are considered adiabatic. Electrons are assumed to be isothermal in all cases. The linear characteristics and Landau damping rates for DIAWs and DAWs are investigated with effects of the dust particle concentrations and different temperature ratios. It is noted that for higher values of positive dust concentration, DIAWs (DAWs) are less (more) damped. It is also observed that the damping rate increases (decreases) as Ti approaches Te for DIAWs (DAWs). It is worth adding here that the theoretical results presented here are supported by numerical analyses and illustrations. The relevance of the study to laboratory and cosmic plasmas is also pointed out. 相似文献
12.
13.
Zhong Ding 《中国物理 B》2022,31(7):70304-070304
We study the single-photon blockade (1PB), two-photon blockade (2PB), and photon-induced tunneling (PIT) effects in a cavity-atom optomechanical system in which a two-level atom is coupled to a single-model cavity field via a two-photon interaction. By analyzing the eigenenergy spectrum of the system, we obtain a perfect 1PB with a high occupancy probability of single-photon excitation, which means that a high-quality and efficient single-photon source can be generated. However, PIT often occurs in many cases when we consider 2PB in analogy to 1PB. In addition, we find that a 2PB region will present in the optomechanical system, which can be proved by calculating the correlation function of the model analytically. 相似文献
14.
Neutrino-photon processes, forbidden in vacuum, can take place in the presence of a thermal medium and/or an external electro-magnetic
field, mediated by the corresponding charged leptons (real or virtual). Such interactions affect the propagation of neutrinos
through a magnetized plasma. We investigate the neutrino-photon absorptive processes, at the one-loop level, for massless
neutrinos in a weakly magnetized plasma. We find that there is no correction to the absorptive part of the axial-vector-vector
amplitude due to the presence of a magnetic field, to the linear order in the field strength. 相似文献
15.
16.
极化中子照相技术通过分析极化中子束的自旋相移对样品磁场进行成像, 自旋极化/分析装置是照相系统的主要组成部分. 引入中子自旋极化/分析装置的极化效率参数, 从中子极化矢量与磁场相互作用机理出发, 重新推导探测中子强度与磁场分布的定量关系, 利用谱仪模拟软件VITESS, 选取bender型超镜极化器和 3He 自旋过滤器作为极化/分析装置, 对量化修正式进行验证, 并综合装置极化效率、单色器能量分辨精度和bender型极化器的几何结构等参数, 初步分析极化中子照相技术的磁场定量检测能力, 相关结果可为极化中子照相的实验数据处理技术研究及装置设计提供参考.
关键词:
极化效率
中子照相
磁场成像 相似文献
17.
We investigate the electron-positron plasma for terahertz radiation generation by two Dark Hollow Gaussian beams (DHGBs), which result in multifocal radiations quite useful for various modern applications. In this process, the ponderomotive force acts as a driver for the generation of terahertz field and the realistic situation of collisional plasma under the application of axial magnetic field reveals an efficient radiation generation. An appreciable efficiency of more than 2% is achieved for the process. 相似文献
18.
反场构形(FRC)预加热磁化等离子体是磁化靶聚变(MTF)中等离子体靶的主要形成方法之一。为了从物理机理及物理本质上更好地理解反场构形磁化等离子体的平衡状态,依据FRC等离子体的经典刚性转子(RR)模型,通过对平衡状态的解析求解,获得了等离子体各主要参数在平衡状态下的分布函数,并与标准二维磁流体力学(MHD)的数值模拟结果进行对比分析,在此基础上讨论了RR模型参数对平衡状态分布函数的影响。结果表明,在FRC等离子体分界线内部,RR解析模型可以较好地描述等离子体状态分布。 相似文献
19.
本文建立了偏分复用系统中偏振模色散与信号偏振态变化引起信道串扰的数学模型, 分析了偏振模色散对偏分复用信道射频功率的影响, 并提出了适用于偏分复用系统的光域偏振模色散补偿与偏分解复用同时进行的方案: 用信道的射频功率作为反馈控制信号, 监测链路中偏振模色散和偏振态变化引起的信道串扰的大小, 用改进的粒子群优化算法对偏振控制器进行自适应控制, 同时完成偏振模色散补偿与偏分解复用. 在112 Gb/s偏分复用-差分正交相移键控(PDM-DQPSK)传输系统中仿真验证了该方案的有效性. 结果表明该方案可以使112 Gb/s-PDM-DQPSK传输系统完成自适应偏分解复用的同时, 在1 dB的光信噪比代价下, 使系统对偏振模色散的容忍度提高20 ps.
关键词:
偏分复用系统
信道串扰
偏振模色散
偏分解复用 相似文献