Nonlinear propagation of neutrinos in a strongly magnetized medium

The nonlinear propagation of an intense neutrino flux in an electron-positron plasma with equilibrium density and magnetic field inhomogeneities is considered. It is found that the neutrinos are nonlinearly coupled with electrostatic and electromagnetic disturbances due to weak Fermi interaction and ponderomotive forces. The process is governed by a Klein-Gordon equation for the neutrino flux and a wave equation for the plasma oscillations in the presence of the ponderomotive force of the neutrinos. This pair of equations is then used to derive a nonlinear dispersion relation which exhibits that nonthermal electrostatic and electromagnetic fluctuations are created on account of the energy density of the neutrinos. The relevance of our investigation to the anomalous absorption of neutrinos in a nonuniform magnetized medium is pointed out.     

Neutrino-driven streaming instability of spin waves in dense magnetized plasma

The spin effects on electromagnetic waves in a strongly magnetized plasma with rare collisions are considered with the help of relativistic kinetic equations, which take into account the electron spin dynamics in self-consistent electric and magnetic fields. The growth rate of the electromagnetic spin waves in the presence of intense quasi-monoenergetic fluxes of neutrinos is determined.     

Neutrino interaction with strongly magnetized electron-positron plasma

A study is made of a complete set of neutrino-electron processes in a magnetized plasma. It is shown that processes involving neutrinos in the initial and final states ve ^? → ve ^? and v ? ve ^? e ⁺ have kinematic amplification in the ultrarelativistic limit. Relatively simple expressions are obtained for the probability and average neutrino energy-momentum loss which are convenient for quantitative analysis. It is observed that the total contribution of ve processes did not depend on the chemical potential of the magnetized electron-positron plasma.     

Dynamics of ionization processes during the interaction of a microwave pulse with plasma near hybrid resonance

We experimentally investigated the dynamics of ionization processes and the formation of a plasma wave channel during the interaction of intense microwave pulses with a magnetized inhomogeneous plasma in the presence of hybrid resonance. The competition between fast electron and slow ionization plasma nonlinearities was studied under conditions when the electron oscillation energy in the wave field was much higher than the atomic ionization energy of the working gas.     

Effective potential for highly relativistic neutrinos in a weakly magnetized medium and their oscillation

We have calculated the effective potential experienced by highly relativistic neutrinos in a weakly magnetized electron–positron plasma, where a momentum-dependent finite-width correction to the propagator of W is considered to account for the threshold effect. Magnetars are believed to be sources of TeV–PeV neutrinos which are produced due to photomeson and proton–proton interactions in their atmosphere. We have studied the resonant-oscillation process ν _e ↔ ν _μ,τ of the highly relativistic neutrinos in the atmosphere of SGR 1806-20, which is a magnetar. It is shown that, for high-energy neutrinos propagating within the magnetar atmosphere, the resonance condition can never be satisfied. On the other hand, if GeV neutrinos are produced deep inside the magnetar atmosphere, where the temperature is about 50 keV or more, then these neutrinos can undergo resonant oscillation.     

Observation of magnetically induced transparency in a classical magnetized plasma

We report the first demonstration of magnetically induced transmission in an opaque magnetized plasma. Magnetically induced transmission in a plasma is a classical analog to the electromagnetically induced transparency in atomic systems. The transmission of radiation through an axially magnetized plasma is obtained by applying an additional one dimensional transverse spatial periodic magnetic field. The transverse-periodic magnetic field uncouples the right-hand electromagnetic wave from interacting with plasma electrons, rendering the plasma band-stop transparent. This provides means to control the extent of absorption of electromagnetic radiation in magnetized plasma.     

Neutrino Self-Energy and Index of Refraction in Strong Magnetic Field: A New Approach

The Ritus E_p eigenfunction method is extended to the case of spin-1 charged particles in a constant electromagnetic field and used to calculate the one-loop neutrino self-energy in the presence of a strong magnetic field. From the obtained self-energy, the neutrino dispersion relation and index of refraction in the magnetized vacuum are determined within the field range m²_e?eB?M²_W. The propagation of neutrinos in the magnetized vacuum is anisotropic due to the dependence of the index of refraction on the angle between the directions of the neutrino momentum and the external field. Possible cosmological implications of the results are discussed.     

Frequency upshifting by an ionization front in a magnetized plasma

The interaction of a light wave with a relativistic ionization front in the presence of an applied DC magnetic field which is perpendicular or parallel to the incident wave is considered. In both cases, four transmitted modes are generated in the magnetized plasma by an incident linearly polarized wave. The frequency upshifts of the various modes are calculated and compared to the unmagnetized case. The corresponding reflection and transmission coefficients are also obtained. Finally, the density ripple associated with the free streaming mode in a magnetized plasma for the perpendicular case is discussed     

Self-Focusing and de-Focusing of Intense Left- and Right-Hand Polarized Laser Pulse in Hot Magnetized Plasma in the Presence of an External Non-Uniform Magnetized Field

In this paper, self-focusing of an intense circularly polarized laser beam in the presence of a non-uniform positive guide magnetic field with slope constant parameter δ in hot magnetized plasma, using Maxwell’s equations and relativistic fluid momentum equation is investigated. An envelope equation governing the spot-size of laser beam for both of left- and right-hand polarizations has been derived, and the effects of the plasma temperature and magnetic field on the electron density distribution of hot plasma with respect to variation of normalized laser spot-size has been studied. Numerical results show that self-focusing is better increased in the presence of an external non-uniform magnetic field. Moreover, in plasma density profile, self-focusing of the laser pulse improves in comparison with no non-uniform magnetic field. Also, with increasing slope of constant parameter of the non-uniform magnetic field, the self-focusing increases, and subsequently, the spot-size of laser pulse propagated through the hot magnetized plasma decreases.     

Rotational energy conversion and thermal evolution of neutron stars

Pulsars are rapidly spinning, strongly magnetized neutron stars. Their electromagnetic dipole radiation is usually assumed to be at the expense of the rotational energy. In this work, we consider a new channel through which rotational energy could be radiated away directly via neutrinos. With this new energy conversion channel, we can improve the chemical heating mechanism that originates in the deviation from β equilibrium due to spin-down compression. The improved chemical and thermal evolution equations with different magnetic field strengths are solved numerically. The results show that the new energy conversion channel could raise the surface temperature of neutron stars, especially for weak field stars at later stages of their evolution. Moreover, our results indicate that the new energy conversion channel induced by the non-equilibrium reaction processes should be taken into account in the study of thermal evolution.     

磁化等离子体光子晶体的FDTD分析

磁化等离子体光子晶体是磁化等离子体和介质(真空)构成的人工周期性结构.本文用磁化等离子体的分段线形电流密度卷积(PLCDRC)时域有限差分(FDTD)算法分析了磁化等离子体光子晶体特性.分析了磁化等离子体参数对电磁带隙的影响.从时域的角度分析了高斯脉冲在磁化等离子体光子晶体中的传播过程，给出了时域反射和透射波形.从频域的角度给出了磁化等离子体光子晶体的电磁反射系数和透射系数，并对结果进行了分析. 关键词： 磁化等离子体 光子晶体 时域有限差分法     

A parametrically unstable mode in magnetized plasmas

It is shown that a homogeneous magnetized plasma can be electrostatically unstable in the presence of a high frequency pump wave perpendicular to the constant external magnetic field.     

Developing a procedure for calculating physical processes in combined schemes of plasma magneto–inertial confinement

A combined scheme of hot plasma confinement is proposed, and laser and plasma-based methods for generating a megagauss field during the implosion of a magnetized target are described that allow the development of new high-density plasma sources for materials science experiments and advanced areas of power engineering. A procedure for numerical calculation of the physical processes involved in the target plasma in an external magnetic field is presented.     

Stationary rarefaction wave in magnetized Hall plasmas

We demonstrate the existence of a stationary rarefaction wave in a current-carrying plasma. The result unexpectedly mismatches with the commonly accepted viewpoint about the impossibility of rarefaction shocks in gases or plasmas. The discovered wave may appear when the magnetic field has penetrated into the plasma and magnetized the electrons. At this stage, the wave front is formed at the cathode and propagates towards the anode through the magnetized quasineutral plasma. The case of low collisionality is investigated analytically. This phenomenon could explain the recent surprising experimental observations of a local plasma density drop in several laboratory plasmas.     

Comparison of the directional characteristics of swift ion excitation for two small biomolecules: glycine and alanine

The characteristics of ions that enter the plasma sheath with an oblique incident angle have been investigated in the presence of an external magnetic field. The ion dynamics in a collisional and collisionless magnetized plasma sheath have been numerically calculated by using a fluid model. Several values for the ion velocity at the sheath edge, orientation and strength of the magnetic field and the ion-neutral collision frequency have been considered. The results show that in a collisionless magnetized plasma sheath, the behaviour of ions that obliquely enter the sheath with some specific velocities at the sheath edge and at some specific orientations and strengths of magnetic field, is more complicated than that of ions with normal entrance angles. For the oblique entrance of ions, the weak magnetic fields cause some fluctuations in ion velocity around its boundary value, i.e. the ion velocity does not accelerate. However, the numerical calculations show that the ion dynamics in a collisional magnetized plasma sheath are the same for both normal and inclined entrance of ions into the sheath.     

High- and low-confinement modes in simple magnetized toroidal plasmas

Three-field simulations of interchange turbulence are presented for a simple magnetized toroidal plasma with a vertical magnetic field. The simulations show the presence of two turbulent regimes characterized by low (L) and high (H) confinement properties. We evaluate analytically the properties of the L regime, obtaining expressions for the plasma gradients and for the density and heat fluxes that agree well with the simulations. By increasing the plasma source strength or reducing the vertical magnetic field, a transition to a H regime occurs, in which a strong velocity shear limits the perpendicular transport with respect to the L scaling and the plasma profiles steepen. The analytic estimate of the transition condition is in accord with the simulations.     

Electromagnetic radiation from filamentary sources in the presence of axially magnetized cylindrical plasma scatterers

Electromagnetic radiation from filamentary electric-dipole and magnetic-current sources of infinite length in the presence of gyrotropic cylindrical scatterers in the surrounding free space is studied. The scatterers are assumed to be infinitely long, axially magnetized circular plasma columns parallel to the axis of the filamentary source. The field and the radiation pattern of each source are calculated in the case where the source frequency is equal to one of the surface plasmon resonance frequencies of the cylindrical scatterers. It is shown that the presence of even a single resonant magnetized plasma scatterer of small electrical radius or a few such scatterers significantly affects the total fields of the filamentary sources, so that their radiation patterns become essentially different from those in the absence of scatterers or the presence of isotropic scatterers of the same shape and size. It is concluded that the radiation characteristics of the considered sources can efficiently be controlled using their resonance interaction with the neighboring gyrotropic scatterers.     

Numerical analysis of the reflection and absorption of electromagnetic wave in nonuniform magnetized plasma slab

In this paper, a model for calculating the reflection and absorption powers of electromagnetic wave (EM wave) in nonuniform magnetized plasma slab is given out based on layer propagation theory. The effects of various plasma parameters and different values of magnetic field intensity on the reflected and absorbed powers are discussed. The results illustrate that the thickness of plasma seldom affects the reflection of radar wave, but it can broaden or reduce the absorption width. Meanwhile, the background magnetic field intensity has an influence upon the results, and it could change the resonance spectrum of magnetized plasma. We also find out that, with appropriate plasma density, collision frequency and magnetic field intensity, more than 90% of radar wave power can be absorbed and the resonant absorption band is about 2 GHz.     

强激光产生的强磁场及其对弓激波的影响

强激光照射金属线圈后,会在打靶点附近的背景等离子体中诱发冷电子的回流,在金属丝内形成强电流源,从而产生强磁场.本文利用神光II高功率激光器产生的强激光照射金属丝靶,产生了围绕金属丝的环形强磁场.利用B-dot对局域磁感应强度进行了测量,根据测量结果,结合三维模拟程序,反演得到磁场的空间分布.再利用强激光与CH平面靶相互作用产生的超音速等离子体撞击该金属丝,产生了弓激波.通过光学成像手段研究了磁场对冲击波的影响,发现磁场使得弓激波的轮廓变得不明显并且张角变大.同时,通过实验室天体物理定标率,将金属丝表面等离子参数变换到相应的天体参数中,结果证明利用该实验方法可以在实验室中产生类似太阳风的磁化等离子体.