Thomson scattering off a pair （electron-positron） plasma

Thomson scattering off a pair (electron--positron) plasma is theoretically investigated in the collisionless and collisional limits respectively. Our calculations show that the power spectrum of the Thomson scattering off a collisionless pair plasma is just proportional to the velocity distribution function of the particles in the plasma. Collective modes in the plasma do not have any effects on the Thomson scattering spectrum because of the correlation between the negatively- and positively-charged particles. In the collisional limit, the power spectrum of the Thomson scattering presents three spikes: two peaks correspond to two contra-propagating sound waves and one peak corresponds to an entropy wave.     

Laser field absorption in self-generated electron-positron pair plasma

Recently, much attention has been attracted to the problem of limitations on the attainable intensity of high power lasers [A.?M. Fedotov et al., Phys. Rev. Lett. 105, 080402 (2010)]. The laser energy can be absorbed by electron-positron pair plasma produced from a seed by a strong laser field via the development of the electromagnetic cascades. The numerical model for a self-consistent study of electron-positron pair plasma dynamics is developed. Strong absorption of the laser energy in self-generated overdense electron-positron pair plasma is demonstrated. It is shown that the absorption becomes important for a not extremely high laser intensity I ～ 10(24) W/cm(2) achievable in the near future.     

The competition of neutrino energy loss due to the pair, photo-, plasma process at the late stages of stellar evolution

Based on the Weinberg-Salam theory, the competition of the Neutrino Energy Loss （NEL） rates due to the pair, photo-and plasma process are canvassed. The ratio factor C1, C2 and C3 which correspond the different contributions of the pair, photo-and plasma neutrino process to those of the total NEL rates are accurately taken into account. The ratio factors are very sensitive to the temperature and density. The ratio factor C2 always is lower than the ratio factor C1 and C3. The pair NEL process is the dominant contribution before the crossed point 0（C1 = C3 = 0.45） and the plasma NEL process will be the main dominant contribution after the crossed point O. With increasing temperature, the crossed point O will move to the direction of higher density.     

液-液萃取反相离子对色谱法测定口腔崩解片剂中溴吡斯的明的血浆浓度

建立了反相离子对色谱法测定口腔崩解片剂中溴吡斯的明血浆浓度的方法.血浆样品经液-液萃取法处理,采用反相离子对色谱法分离,以溴新斯的明作为内标定量.实验结果显示溴吡斯的明和内标物洗脱时间分别为5.63min和9.76min,与血浆中内源性杂质良好分离.溴吡斯的明线性范围为0.02-2.00mg· L-1 (n=7,r=0...     

The competition of neutrino energy loss due to the pair,photo-,plasma process at the late stages of stellar evolution

Based on the Weinberg-Salam theory,the competition of the Neutrino Energy Loss (NEL) rates due to the pair,photo- and plasma process are canvassed.The ratio factor C1,C2 and C3 which correspond the different contributions of the pair,photo- and plasma neutrino process to those of the total NEL rates are accurately taken into account.The ratio factors are very sensitive to the temperature and density.The ratio factor C2 always is lower than the ratio factor C1 and C3.The pair NEL process is the dominant contribution before the crossed point O(C1=C3=0.45) and the plasma NEL process will be the main dominant contribution after the crossed point O.With increasing temperature,the crossed point O will move to the direction of higher density.     

Experiments on the propagation of lower hybrid waves in a toroidal plasma

The propagation of the lower hybrid waves is investigated in a toroidal afterglow plasma by using a pair of the half-turned strip lines. It is confirmed that experimental results of propagation in a toroidal plasma well agree with calculated ones from the cold plasma theory.     

Quantum effects with an x-ray free-electron laser

A quantum kinetic equation coupled with Maxwell's equation is used to estimate the laser power required at an x-ray free-electron laser (XFEL) facility to expose intrinsically quantum effects in the process of QED vacuum decay via spontaneous pair production. A 9 -TW-peak XFEL laser with photon energy of 8.3 keV could be sufficient to initiate particle accumulation and the consequent formation of a plasma of spontaneously produced pairs. The evolution of the particle number in the plasma will exhibit non-Markovian aspects of the strong-field pair production process, and the plasma's internal currents will generate an electric field whose interference with that of the laser leads to plasma oscillations.     

辐射在各向异性等离子体中散射的结构因子

本文导出多组元各向异性等离子体中二体密度关联函数的计算公式,求得双麦克斯韦等离子体中考虑了电子-电子和电子-离子关联效应的电子-电子密度关联函数,最后给出电磁辐射在各向异性等离子体中散射的结构因子。 关键词：     

A new possible mechanism of lepton-pair radiation from quark-gluon plasmas

The lepton-pair production mechanism resulting from escaping quarks interacting with a collective confining colour field is discussed. The pair production rate is estimated and the spectrum of pair invariant mass is calculated. It is suggested that measuring the angle asymmetry of radiated lepton-pairs could indicate quark-gluon plasma formation.     

Electron and positron nonthermality effects on the formation of damped solitons in collisional multi-component plasmas

Electrostatic damped field characteristics in non-thermal fast positron and electron plasma having fluids of positive and negative pair ions have been discussed when collisional frequencies parameters are taken into account. The damped and forced form of Kadomtsev-Petviashvili (DKP) equations have been obtained. The plasma parameters effects of electron density ratio, the negative ionic density ratio, the pair ionic charge ratio, the density of positron ratio, the collisional frequencies, ion mass ratio and the fast non-thermality on the electrostatic damped and forced field formations, as observed in D-F -ionosphere and laboratory experiments have been investigated.     

Pair production and optical lasers

Electron-positron pair creation in a standing wave is explored using a parameter-free quantum kinetic equation. Field strengths and frequencies corresponding to modern optical lasers induce a material polarization of the QED vacuum, which may be characterized as a plasma of e+e- quasiparticle pairs with a density of approximately 10(20) cm-3. The plasma vanishes almost completely when the laser field is zero, leaving a very small residual pair density n(r) which is the true manifestation of vacuum decay. The average pair density per period is proportional to the laser intensity but independent of the frequency nu. The density of residual pairs also grows with laser intensity but n(r) proportional to nu(2). With optical lasers at the forefront of the current generation, these dynamical QED vacuum effects can plausibly generate 5-10 observable two-photon annihilation events per laser pulse.     

Analysis of a 2D “liquid” plasma lattice

To study the structural and dynamical properties of a 2D dusty plasma lattice, a set of experiments were performed in an environment of radio frequency discharge. Based on the results of one of the experiments, pair correlation function, bond-orientational correlation function and mean square displacement of such a system were computed and analyzed. The bond-orientational correlation function is found to fit in with the law of e-r, and the mean square displacement is found to increase monotonously with time, both of which, together with the pair correlation function, indicate that the two-dimensional dusty plasma lattice formed in the experiment stayed in a "liquid" state.     

Photon bremsstrahlung from an extreme relativistic hydrogen plasma

The effect of the electron-positron pair creation on the intensity of radiation by an extreme relativistic plasma is studied. The degeneracy of the electron and positron gases is taken into account. It is found that the pair creation is of considerable importance for both the quantity and temperature dependence of the radiation intensity.Dedicated to Professor V. Votruba on his sixtieth birthday.     

Quantum-electrodynamical photon splitting in magnetized nonlinear pair plasmas

We present for the first time the nonlinear dynamics of quantum electrodynamic (QED) photon splitting in a strongly magnetized electron-positron (pair) plasma. By using a QED corrected Maxwell equation, we derive a set of equations that exhibit nonlinear couplings between electromagnetic (EM) waves due to nonlinear plasma currents and QED polarization and magnetization effects. Numerical analyses of our coupled nonlinear EM wave equations reveal the possibility of a more efficient decay channel, as well as new features of energy exchange among the three EM modes that are nonlinearly interacting in magnetized pair plasmas. Possible applications of our investigation to astrophysical settings, such as magnetars, are pointed out.     

Attraction of positively charged particles in highly collisional plasmas

It is shown that the electrostatic interaction potential between a pair of positively charged particles embedded in a highly collisional plasma has a long-range attractive asymptote. The effect is due to continuous plasma absorption on the particles. The relevance of this result to experimental investigations of complex (dusty) plasmas is discussed.     

等离子体双频点微波透射衰减诊断法

介绍了利用非磁化等离子体中微波在两个相邻波长处的透射衰减值来反推该等离子体频率(从而得到电子密度)和电子碰撞频率的方法───双频点微波透射衰减诊断方法。陈述了利用扫频信号源、标量网络分析仪和宽带喇叭天线等构成的系统对微波衰减测量的过程,对该方法的诊断误差进行了讨论。双频点微波透射衰减诊断法适用于大气压等离子体的初步诊断。     

Dynamical behaviour of transverse plasmons in pair plasmas

This paper analytically investigates the nonlinear behaviour of transverse plasmons in pair plasmas on the basis of the nonlinear governing equations obtained from Vlasov--Maxwell equations. It shows that high frequency transverse plasmons are modulationally unstable with respect to the uniform state of the pair plasma. Such an instability would cause wave field collapse into a localized region. During the collapse process, ponderomotive expulsion is greatly enhanced for the increase of wave field strength, leading to the formation of localized density cavitons which are significant for the future experimental research in the interaction between high frequency electromagnetic waves and pair plasmas.     

一种基于单负Metamaterials成对结构的带通滤波器的设计

提出了一种基于单负Metamaterials对的带通滤波器的设计原理,给出了这种带通滤波器的谐振频率的表达式,对其谐振频率及带宽与其决定因素之间的关系进行了计算,对计算结果进行了讨论,为设计单负Metamaterial对带通滤波器的理论与方法提供了依据。研究结果表明：利用单负Metamaterials对的确可以实现带通滤波器;ENG板的磁导率μ1、MNG板的介电常数ε2、电等离子体频率ωep、磁等离子体频率ωmp、两个层的厚度比值a这五个因素决定了这种滤波器的中心频率;两个层的厚度及二者之间的比值决定这种滤波器的带宽。     

Pair correlation function in a dense plasma and pycnonuclear reactions in stars

The short-range behavior of the pair correlation function in a dense onecomponent plasma (jellium) is investigated. As an intermediate step, the short-range behavior of the classical pair correlation function is obtained. Actually, although the temperature and the density are assumed to be such that the thermodynamic properties are almost classical, quantum mechanics (tunnel effect) always dominates the pair correlation function at short distances. The quantum pair correlation function is calculated by treating the many-body quantum effects by a perturbation theory, and by using a semiclassical approximation based on path integrals. The results are applied to the computation of the nuclear reaction rate in dense stellar matter (pycnonuclear reactions).Laboratoire associé au Centre National de la Recherche Scientifique.     

Pair annihilation effects on dust ion acoustic surface wave in semi-bounded magnetized pair–ion–dust plasmas

The electron–positron pair annihilation effects on the dust ion acoustic surface wave are investigated in semi-bounded magnetized electron–positron–ion–dust plasmas. The dispersion relation of the low frequency dust ion acoustic surface wave is obtained by the plasma dielectric function with the specular reflection boundary condition. The results show that the frequency of the dust ion acoustic surface wave is found to be increased with increasing the annihilation of the electron–positron pair. In addition, the group velocity of the dust ion acoustic surface wave is also found to be increased with the annihilation of the electron–positron pair.