Effect of the proton mass on the spectrum of the hydrogen atom in a strong magnetic field

Contrary to a recent claim, we point out that, in the problem of a hydrogen atom in a strong magnetic field, the centre-of-mass motion and the relative motion of the particles can be separated, and that the effect of the finite proton mass on the spectrum is negligible.     

Relativistic theory of inverse beta-decay of polarized neutron in strong magnetic field

The relativistic theory of the inverse beta-decay of polarized neutron,ν _e +n → > p +e ^-, in strong magnetic field is developed. For the proton wave function we use the exact solution of the Dirac equation in the magnetic filed that enables us to account exactly for effects of the proton momentum quantization in the magnetic field and also for the proton recoil motion. The effect of nucleons anomalous magnetic moments in strong magnetic fields is also discussed. We examine the cross-section for different energies and directions of propagation of the initial neutrino accounting for neutron polarization. It is shown that in the super-strong magnetic field the totally polarized neutron matter is transparent for neutrinos propagating antiparallel to the direction of polarization. The developed relativistic approach can be used for calculations of cross-sections of the other URCA processes in strong magnetic fields.     

Beam dynamics study in the C235 cyclotron for proton therapy

A study of the beam dynamics in the C235 (T06) cyclotron made for proton therapy is presented. Results of the computer simulations of the particle motion in the measured magnetic field are given. A study of the resonance influence on the acceleration process was carried out. The corresponding tolerances on the magnetic field imperfections and transverse beam parameters were defined using these simulations. The text was submitted by the authors in English.     

Suppression of the ideality of degenerate Fermi-gases of charged particles in the quantum limit of a very intense magnetic field

It is shown that, in the quantum limit of a very intense magnetic field, the kinetic energy of free motion of charged Fermi-particles falls as the field strength increases. For degenerate nonrelativistic gases of equal concentrations a proton gas becomes nonideal for considerably lower values of the magnetic-field strength than for an electron gas of the same concentration.A. S. Pushkin Brest State Pedagogical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 102–106, January, 1994.     

Anisotropic features of two-dimensional hydrogen atom in magnetic field

The aim of this study is the numerical research of anisotropic characteristics of a two-dimensional (2D) hydrogen atom induced by a magnetic field. The ground state energy (GSE) of the 2D hydrogen atom and the corresponding wavefunction have been numerically calculated in the Born–Oppenheimer approximation and taking into account the finite proton mass. The nonlinear dependence of the GSE on angle α between the magnetic field vector and the normal to the electron motion plane has been found in a wide range of the magnetic field. The effect of a significant reduction of the GSE (up to 1.9-fold) is observed with increasing the angle α up to 90°. The agreement with experimental data has been demonstrated. The dependences of the GSE of a 2D exciton in GaAs/Al_0.33Ga_0.67As have been determined for various tilt angles and magnetic fields.     

Proton heating via nonresonant scattering off intrinsic Alfvénic turbulence

A novel yet unsophisticated theory is proposed to show that low-beta protons can be efficiently heated by enhanced Alfvén waves. The present research is motivated by a plasma physics issue relevant to the explanation of hot stellar coronas observed with x-ray telescopes. The efficient heating is attributed to nonresonant wave-particle scattering that tends to randomize proton motion in directions transverse to the ambient magnetic field.     

考虑磁透镜边缘场的质子成像系统优化设计

高能质子照相系统由四极磁透镜和准直器组成,实际透镜的边缘场将影响成像系统的性能.本文将含边缘场的磁场梯度用贝尔函数近似,提出了一种含边缘场的成像系统优化方法.通过Geant 4程序模拟了能量为1.6 GeV的质子成像系统,并通过优化方法给出了考虑边缘场的优化后的系统参数.研究了考虑边缘场时的成像系统参数对准直器孔径的影...     

激光质子照相特性模拟研究

基于超短激光驱动的质子源的照相技术是传统质子照相技术的发展. 使用FLUKA蒙特卡罗（MC）程序,依据激光质子源的特点,对质子照相进行了定量的模拟研究. 通过对三种典型情况的模拟 （半平面靶及台阶靶,激光惯性约束聚变研究用黑腔,磁场网格照相） 分析了影响质子照相的主要物理因素, 表明了激光质子照相具有对界面敏感,高空间分辨,对磁场敏感的优点. 关键词： 超短激光 质子照相 蒙特卡罗     

Numerical studies of charged particles in a magnetic field: Mars application

An approach to model the Martian magnetization can be done using classical source models. Classical models, such as uniformly magnetized spheres and cylinders, allow for the introduction of additional constraints related to the available information of the magnetic field and its sources. The use of a suitable conservative numerical scheme in Cartesian coordinates was carried out for numerical studies. In this work the motion of different charged particles under the influence of different magnetized sources have been analyzed by using the proposed numerical scheme. For that purpose, electron, proton and alpha particles were used. In addition, the impact of the gravitational effect on the particles motion was also studied.     

Double resonance experiments in low magnetic field: Dynamic polarization of protons by N and measurement of low NQR frequencies

The possibilities of dynamically polarizing proton spin system via the quadrupole ¹⁴N spin system in low magnetic field are analyzed. The increase of the proton magnetization is calculated. The polarization rate of the proton spin system is related to the transition probabilities per unit time between the ¹⁴N quadrupole energy levels and proton energy levels. The experiments performed in 1,3,5-triazine confirm the results of the theoretical analysis. A new double resonance technique is proposed for the measurement of nuclear quadrupole resonance frequencies ν_Q of the order of 100 kHz and lower. The technique is based on magnetic field cycling between a high and a low static magnetic field and observation of the proton NMR signal in the high magnetic field. In the low magnetic field the quadrupole nuclei and protons resonantly interact at the proton Larmor frequency ν_H = ν_Q/2. The quadrupole nuclei are simultaneously excited by a resonant rf magnetic field oriented along the direction of the low static magnetic field. The experimental procedure is described and the sensitivity of the new technique is estimated. Some examples of the measurement of low ¹⁴N and ²H nuclear quadrupole resonance frequencies are presented.     

拉曼型自由电子激光器中相对论电子运动稳定性的比较研究

拉曼型自由电子激光器作为一种兆瓦级高功率毫米波、太赫兹波辐射源, 其电子的运动稳定性对整体器件的性能至关重要.本文采用科尔莫戈罗夫熵方法, 以典型的麻省理工学院公布的实验数据为例, 比较研究拉曼型正向导引磁场和反向导引磁场两类自由电子激光器中相对论电子的运动稳定性. 结果表明:摇摆器绝热压缩磁场对电子运动的稳定性无实质性影响, 但对电子运动影响大; 电子束自身场在拉曼型正向导引磁场自由电子激光器中使电子运动稳定性变差, 而在拉曼型反向导引磁场自由电子激光器中则可改善电子运动稳定性. 关键词： 拉曼型自由电子激光器 相对论电子运动稳定性 科尔莫戈罗夫熵 电子束自身场     

The conductivity properties of protons in ice and mechanism of magnetization of liquid water

From a study of electrical conductivity of protons in the hydrogen-bonded chains in ice we confirm that the magnetization of liquid water is caused by proton transfer in closed hydrogen-bonded chains occurring as a first order phase transition, through which the ice becomes liquid water. We first study the conductive properties of proton transfer along molecular chains in ice crystals in our model. Ice is a typical hydrogen-bonded molecular system, in which the interaction of localized fluctuation of hydrogen ions (H⁺) with deformation of a structure of hydroxyl group (OH) results in soliton motion of the protons along the molecular chains via ionic and bonded defects. We explain further the quantum conductive properties of proton transfer and determine its mobility and conductivity under constant electric-field using a new theory of proton transfer, which agree with experimental values. From features of first order phase-transition for ice, and some experimental data of pure and magnetized water we confirm further that there are not only free water molecules, but also many linear and closed hydrogen-bonded chains consisting of many polarized water-molecules in the liquid water. Thus a ring proton-current, which resembles to a “molecular current” or a “small magnet” in solids, can occur in the closed hydrogen-bond chains under action of an externally applied magnetic field. Then the water molecules in the closed chains can be orderly arrayed due to the magnetic interaction among these ring proton currents and the externally applied magnetic field. This is just the magnetized effect of the water. In such a case the optical and electronic properties of the water, including the dielectric constant, magnetoconductivity, refraction index, Raman and Infrared absorption spectra, are changed. We determine experimentally the properties of the magnetized water which agree with the theoretical results of our model. However, the magnetized effect of water is, in general, very small, and vanishes at temperatures above 100 ^○C.     

Magnetic dipole excitation mode according to the collective model with separate neutron and proton deformations

The collective model with separate neutron and proton deformations is developed. The collective motion of individual neutron and proton surfaces is reduced to the motion of the mass surface and the neutron skin. The strong coupling scheme of the neutron skin vibrations to the mass-surface motion is applied for well-deformed nuclei. The magnetic dipole excitation mode, which was discovered experimentally, is explained as theK = 1 one-phonon neutron skin vibration in a deformed nucleus. Some estimates of parameters of the model are performed. Finally, the model is confronted with the two-rotor model and the interacting boson model (IBM-2).     

Magneto-optical study of domain wall dynamics and giant Barkhausen jump in magnetic microwires

Investigation of surface domain walls motion in Co-rich magnetic microwires has been performed in circular and axial magnetic fields. The dc axial magnetic field acceleration of the domain wall motion related to the influence of the axial field on the structure of the moving domain wall has been discovered. Pulsed axial magnetic field induced unidirectional motion of surface domain wall also has been found.     

Radial motion of a solid spherical body in a magnetic field

The object of the present paper is to investigate the radial motion of a solid spherical body, assumed to be homogeneous, isotropic and elastic, in presence of a magnetic field in the azimuthal direction. The body is assumed to be in a state of initial stress which is hydrostatic in nature. This theory of radial motion of a solid spherical body in a magnetic field has been utilised to find the small radial motion of a solid Earth assumed to be homogeneous isotropic elastic sphere in presence of a magnetic field in the azimuthal direction. Considering the effect of gravity and the initial stress produced by slow process of creep due to extra masses over the surface of the Earth, the fundamental equations of motion are derived which are non-linear in character and are solved. The times of a desired radial displacement are calculated in presence of a magnetic field only and in presence of the same magnetic field, initial stress and gravitational field, which are compared and exhibited numerically.     

均匀强磁场中中子星物质的物态方程

在Walecka模型的平均场近似下,研究了由质子、中子和电子组成的中子星物质在均匀强磁场中的性质,发现磁场增强,物态方程会在一定程度上变硬,中子所占比例显著增加,质子和电子所占比例会显著减少,磁场对物态方程的影响比它对粒子组分的影响小.本文还分别利用流体力学公式和热力学公式分别计算了中子星物质的压强,发现磁场越强,用这两种方式计算的压强越接近,当磁场为10¹⁴T时,它们完全重合.     

The Equation of State of Neutron Star Matter in Uniform Strong Magnetic Fields

The Walecka model is extended to the neutron star matter, and in it's mean field approximation, the properties of neutron star matter consisted of proton, neutron and electron in uniform strong magnetic fields are studied. it is found that the ~equation of state (eos) becomes stiffer in some degree, and the ratio of neutron increase evidently while the one of proton and electron decrease with the magnetic field being stronger. the influence of the magnetic to the eos is smaller than the one to the fractions of the particles. the pressure of the neutron star matter is calculated by hydrodynamics and thermodynamics respectively. the stronger the magnetic field is, the more adjacent the curves of pressure depicted in these two ways are, and they are in superposition completely when the magnetic field is 10¹⁴T.     

强激光驱动线圈靶磁场产生及应用研究进展

介绍了以强激光驱动电容线圈靶的实验方法产生磁场的基本模型及其发展过程。对比了实验室中常用的三种磁场诊断方法,包含:B-dot、法拉第旋转以及质子背光,发现前两种方法在实验中仅可以获得距离靶较远处的有限个磁场值,通过结合模拟工具获得靶处的磁场值与测量点的值跨越几个数量级,容易产生误差;质子背光诊断可以在实验中获得全局磁场信息,能够较好地满足线圈靶磁场诊断的需求。由于线圈靶磁场强且可持续时间长,在时空分布上具有一定可控性,因此我们将其应用到了磁重联的研究中,并成功获得了重联出流等特征。另外线圈靶在带电粒子的约束和磁流体动力学研究等多方面也得到了应用。     

Suppression of degeneracy of Fermi gases of charged particles in a strong magnetic field

The suppression of degeneracy of ultrarelativistic electron and nonrelativistic proton gases is considered as a function of temperature and magnetic field strength. It is shown that at absolute zero the degeneracy of nonrelativistic proton and relativistic electron gases of equal concentrations is suppressed at the same values of magnetic field strength exceeding considerably the values at which these particles fill the lower Landau level completely.Education Institute, Brest. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 85–90, June, 1992.     

Directed motion of domain walls in biaxial ferromagnets under the influence of periodic external magnetic fields

Directed motion of domain walls (DWs) in a classical biaxial ferromagnet placed under the influence of periodic unbiased external magnetic fields is investigated. Using the symmetry approach developed in this article the necessary conditions for the directed DW motion are found. This motion turns out to be possible if the magnetic field is applied along the easiest axis. The symmetry approach prohibits the directed DW motion if the magnetic field is applied along any of the hard axes. With the help of the soliton perturbation theory and numerical simulations, the average DW velocity as a function of different system parameters such as damping constant, amplitude, and frequency of the external field, is computed.