Dynamics of an ion flow in an electron layer

We study the acceleration of an ion flow in the electron layer formed by an electron flow moving in a transverse electric field and confined by the intrinsic magnetic field. The possibility of extraction of heavy ions with velocities lower than the ion sound velocity from the plasma, and the feasibility of their further acceleration by an external field is demonstrated.     

Scattering of waves by an aperture in an impedance screen

The transmission and diffraction of waves by an aperture in an impedance screen is investigated. The Senior's solution of the scattering problem of waves by an impedance half-plane is transformed into a physical optics type integral. The obtained method is applied to the transmission problem of waves by a slit in an impedance screen. The results are compared with the aperture problem in black and conducting screens numerically.     

Confinement of an Electron in an Image Potential and an External Electrostatic Field

The quasi-classical approximation is used to determine the positions of the classical turning points upon motion of an electron that is bound by an image field and a constant homogeneous electric field of the same direction. Power expansions of the coordinates of the turning points in a wide range of electron energies and field strengths are obtained. The mechanism of one-dimensional confinement of an electron, which determines a completely discrete spectrum of states, is described. The dependence of the spatial width of the confinement region on the field strength and electron energy is determined. The dependences of the electron energy in different states on the external field strength are calculated numerically. Quasi-classical quantization is performed, and the dependence of the electron energy on the width of the confinement region is determined. The energy interval of a maximum density of electron states is found, which is determined by the dependence of the width of the confinement region on the electric field strength.     

Response of an ideal gas in an external potential

We construct the exact solution for the time evolution of the local mass density in an ideal gas in which an external short-ranged separable potential is switched on at time t = 0. The redistribution of matter in strong potentials causing bound states or resonances is studied in great numerical detail.     

Backscattering of an intense laser beam by an electron

We present a novel, simple asymptotic expansion for the spectrum of radiation that is backscattered from a laser by a counterpropagating (or copropagating) electron. The solutions are presented in such a way that they explicitly show the relative merit of using an intense laser and of an energetic electron beam in x-ray production in the single particle regime. Simple scaling laws are given.     

Dynamics of an anchored polymer molecule under an oscillating force

We study the dynamics of a polymer of varying stiffness, pinned or grafted at both ends and subjected to an oscillatory forcing at an intermediate point. Via stochastic simulations, we find a crossover from a periodic limit cycle to an aperiodic dynamics as the polymer gets "stiffer." An analytical argument valid in the 2D grafted case shows that in such a case this aperiodic dynamics has some chaotic signatures.     

非谐射频阱中离子云系统的精确周期解

射频阱中离子云与检测场的相互作用由周期驱动的Duffing方程描述.本文报道了该方程的一个精确的周期解,它描述了阱参数和外场对离子云周期运动的影响.结果表明,在各参变量满足周期解条件时,离子的运动频率为外场频率的三分之一,运动振幅分别与外场频率、振幅以及阱频正相关,与离子阱的非谐参数反相关.     

Diffraction of an ultrashort pulse by an aperture

The scalar problem of diffraction of an infinitely short pulse by a plane screen is solved within Kirchhoff’s approximation. The response of an infinitely small aperture is calculated, and the explicit solution is found for the case of a circular aperture.     

Localized States of an Excess Electron in an Ionic Cluster

A theory of an electron affinity for an ionic cluster is proposed both in a quasiclassical approach and with quantization of a polarization electric field in a nanoparticle. A critical size of the cluster regarding in formation of an electron's autolocalized state, dependencies of energy and radius of a polaron on a cluster's size are obtained by a variational method. It has been found that binding energy of the electron in the cluster depends on a cluster's radius but a radius of electron's auto-localization does not depend on the cluster's radius and it equals to the polaron radius in a corresponding infinity crystal. A bound state of the electron in a cluster is possible only if the cluster's radius is more than the polaron radius.     

Localized States of an Excess Electron in an Ionic Cluster

A theory of an electron affinity for an ionic cluster is proposed both in a quasiclassical approach and with quantization of a polarization electric field in a nanopartiele. A critical size of the cluster regarding in formation of an electron＇s autolocalized state, dependencies of energy and radius of a polaron on a cluster＇s size are obtained by a variational method. It has been found that binding energy of the electron in the cluster depends on a eluster＇s radius but a radius of electron＇s auto-localization does not depend on the cluster＇s radius and it equals to the polaron radius in a corresponding infinity crystal. A bound state of the electron in a cluster is possible only if the duster＇s radius is more than the polaron radius.     

Propagation of an attosecond X-ray pulse in an atomic-scale waveguide

The guiding of an attosecond (as) X-ray pulse in a two-dimensional atomic structure is analyzed. The results obtained from a simple model show that an atomic-scale waveguide which consists of a barium monoxide lattice where five rows of atoms have been removed can successfully guide pulses with duration 20 as and wavelength 10 Å. This is attributed to an improved total external reflection in the discrete atomic structure. When the carrier frequency is higher than the plasma frequency, the guide causes minor distortions in the pulse profile. For lower frequencies, the X-ray pulse is significantly affected by the guide dispersion. These results indicate that nano- and sub-nanostructures can be designed for transportation and processing of coherent attosecond-duration electromagnetic pulses, which is important for the newly emerging field of X-ray photonics.     

Compton scattering of an X-ray photon by an open-shell atom

A nonrelativistic quantum theory for the nonresonant Compton scattering of an X-ray photon by a free many-electron atom with an open shell in the ground state has been constructed in the single-configuration Hartree-Fock approximation outside the impulse approximation widely used in the literature. The transition to an atom with closed shells reproduces the results obtained previously in [6, 7]. The results of a test calculation for atoms with open (Ti, Fe) and closed (Zn) 3d core shells are presented. The effects of the radial relaxation of one-electron states in the field of core vacancies have been taken into account. The results of the calculation agree well with the experimental results [15, 16]. It has been established that the results of the impulse approximation in the investigated X-ray photon energy ranges disagree with those of our theory not only quantitatively but also qualitatively. In particular, the impulse approximation near the elastic (Thomson and Rayleigh) scattering line leads to a gross overestimation of the contributions from the deep atomic shells involved in the inelastic photon scattering only virtually to the scattering probability. The presented theory is general in character and its applicability to a particular element of the Mendeleev table with an open core shell or to a many-electron atomic ion is limited only by the requirement that the nonrelativistic Hartree-Fock approximation be properly used in describing the scattering-state wave functions.     

Surface spin-wave electrodynamics of an easy-axis antiferromagnet in an external electric field

The conditions are found under which quadratic magneto-optic interaction causes the formation of virtual surface magnetic TM and TE polaritons propagating along the interface between an antiferromagnet (AFM) and an ideal metal or between an AFM and an insulator in an external static electric field directed along the easy axis of the AFM. The specific features of the reflection of a bulk electromagnetic wave incident from vacuum onto the AFM surface are studied under these conditions.     

Capture of an atom by an argon cluster: Atomistic simulation

A molecular dynamics simulation of the collision of an argon atom with a neutral cluster Ar _n (n ≤ 400) in an equilibrium system at a temperature of T = 20–35 K has been performed using the classical trajectory method. It has been shown that the total capture cross section under these conditions exceeds the limiting value obtained in the hard-sphere model and approaches it very slowly with an increase in n and T. At the same time, the simulation results are in agreement with the Langevin capture cross section for an atom in the Gspann-Vollmar potential, particularly with allowance for the dependence of the capture probability on the collision rate.     

Splitting of an edge dislocation by an optical vortex

In a linear medium an optical vortex induces the splitting of an edge dislocation into vortices of both topological charges. Their positions and number depend on which of the phase dislocations is shifted from the center of the host beam. Violations of the charge conservation law are discussed.     

Influence of an indefinite causal order on an Otto heat engine

The quantum effect plays an important role in quantum thermodynamics, and recently the application of an indefinite causal order to quantum thermodynamics has attracted much attention. Based on two trapped ions, we propose a scheme to add an indefinite causal order to the isochoric cooling stroke of an Otto engine through reservoir engineering. Then, we observe that the quasi-static efficiency of this heat engine is far beyond the efficiency of a normal Otto heat engine and may reach one. When the power is its maximum, the efficiency is also much higher than that of a normal Otto heat engine. This enhancement may originate from the non-equilibrium of the reservoir and the measurement on the control qubit.     

Dynamics of an Orientational-Kink Pair in a Hydrogen-Bonded Chain in an External Field

We discuss dynamic properties of an orientational-kink pair in hydrogen-bonded chains in the presence of an external force and damping, based on a new two-component soliton model. We study the scattering of an electromagnetic wave by an orientational-kink pair. Finally, we find the expressions of the scattering cross-section of an orientational-kink pair for an electromagnetic wave and the mobility of the orientational-kink pair.     

Total absorption of an electromagnetic wave by an overdense plasma

We show both theoretically and experimentally that an electromagnetic wave can be totally absorbed by an overdense plasma when a subwavelength diffraction grating is placed in front of the plasma surface. The absorption is due to dissipation of surface plasma waves (plasmons polaritons) that have been resonantly excited by the evanescent component of the diffracted electromagnetic wave. The developed theoretical model allows one to determine the conditions for the total absorption.     

Distribution characteristic of scattering field for an ellipsoidal target irradiated by an electromagnetic wave from an arbitrary direction

It is of great importance for engineering applications to obtain the expression of scattering field for an ellipsoidal target irradiated by an electromagnetic wave from an arbitrary direction. Literature relevant to this problem is seldom found. In this paper, the scattering field for an ellipsoidal target is presented by utilizing the scale transformation of electromagnetic field and the rotation of coordinate system, with an electromagnetic wave projecting on the target from an arbitrary direction. The obtained result is in good agreement with the solution available from the literature if we consider the scale factors to be unity. Taking a conducting ellipsoidal target for sample, we perform the partial simulations of the ellipsoidal model and a plant leaf model by choosing different scale factors. The obtained results show that the distribution characteristic of scattering field is sensitively affected by the polarization of the incident wave and varies not much with the incident wave angle but changes with the observation point. At some points the scattering energy arrives at its maximum.