Spatial and angular distribution of the heavy ion charge under channeling in crystals

A kinetic theory of passage of multiply charged heavy ions through crystals is developed that allows for diffusion in the transverse momentum space and ion-crystal charge exchange. The theory provides an adequate explanation for the observed angular distributions of heavy ions passing through oriented crystals, makes it possible to calculate the partial angular distributions of different charge states, and treats the discovered effects of “cooling” and “heating” of channeled ion beams in physical terms. The angular and spatial distribution of channeled ions with different energies is calculated. Whether a channeled beam of multiply charged heavy ions will be cooled or heated is related to the dependence of the electron capture and loss probabilities on the impact parameter when the ions interact with atomic chains. This interaction governs the run of the angular and spatial distribution of the channeled ion charge.     

Spatial structure of solar-wind transition region

Transillumination is employed to study the region of solar-wind transition from subsonic to supersonic flow. Quasars are used as transilluminating sources. Observations were performed in June of 1988 at a wavelength of 2.9 m. Five sources with different heliolatitudes were used. The locations of the internal and external boundaries of the transition region were determined from data on the radial dependence of the angle of radio-wave scattering 2(R). A two dimensional map of the transition region was obtained from this.Institute of Terrestrial Magnetism, the Ionosphere, and Radio-Wave Propagation, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 34, No. 9, pp. 971–974, September, 1991.     

小球与均质自由杆的碰撞

讨论了小球与自由杆碰撞过程中所遵从的物理规律,明确了完全非弹性碰撞过程的能量特征,指出完全非弹性碰撞后两物体不一定粘在一起共同运动的事实.     

Heisenberg's model revisited to study the angular distribution in inelastic hadron hadron collision at high energy

A semi empirical formulation for the angular distribution of the secondaries in inelastic hadronic collision has been proposed. It has been found that the experimental data show remarkable agreement with this formulation in the entire energy region (1 to 10⁴ GeV).The authors gratefully appreciate the helpful suggestions and comments of Prof. A.Wataghin, GENOVA.     

散射体系A+BC的平-振能量传递

用Alhassid与Levine所提出的动力学李代数的方法(简称A-L理论),研究了含有二级非简谐的共线散射体系A+BC的平-振能量传递问题,计算了散射过程含有主要动力学参量的跃迁矩阵和跃迁几率的解析表示式.     

Light particle coincidences with gross structure in energy spectra from the40Ca+40Ca collision

Proton and pion spectra from relativistic heavy ion collisions are calculated in the framework of a hydrochemical model. An explanation of the striking absence of the delta decay pion peak in the observed pion spectra is suggested.     

On the energy distribution and angular distribution of sputtered particles

Abstract

The influence of the anisotropy of the momentum recoil density of collision cascades in solids on the energy and angular distribution of sputtered particles is considered. Various sputtering mechanisms are discussed. For some of those mechanisms this anisotropy leads to deviations from a ε^?2 asymptotic form in the energy distribution and to an asymmetry in the angular distribution as a function of the angle of incidence of the projectile.     

再谈"小球与均质自由杆的碰撞"

讨论了小球在杆上任一点的碰撞问题,并指出《大学物理》2006年第5期《小球与均质自由杆的碰撞》一文中"完全非弹性碰撞后两物体不一定粘在一起共同运动"的说法是错误的.     

Spatial macroscopic structure of a pulsed microsecond discharge in barrier-metal gaps with a nonuniform electric field distribution

Electric and spatial characteristics of a pulse-periodic microsecond barrier discharge are investigated in different geometries—triangular prism, plate, and corrugated electrode—that are in contact with a dielectric plate and form a dihedral angle with it. It is established that, in the space of the dihedral angle, the regions of discharge represent alternating cylindrical layers with the axes lying on the contact line. The first conducting layer is formed at some distance from the contact edge of the electrode. The number of layers and their localization are determined by the angle formed between an electrode and the dielectric plate. A physical model explaining the main features of the structure formation is proposed.     

Determining the optical thickness of a dispersing medium from the angular distribution of radiation scattered from its boundaries

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 6, pp. 983–987, December, 1991.     

Spatial chirp and angular dispersion of the nonlinear crystal for a femtosecond OPO

In this paper spatial chirp and angular dispersion are calculated theoretically and analyzed for a four-mirror, standing-wave cavity femtosecond OPO. The analytical expression of spatial chirp in the nonlinear crystal is deduced. The analytical expressions of second- and third-order dispersion including angular dispersion of the nonlinear crystal are presented, for the noncollinear type-I phase-matched Fs BBO OPO using angle tuning. Moreover, variations of GDD and TOD with cavity parameters are calculated exactly. The analysis method and the obtained result also are efficacious for a same type Fs OPO.     

On the effect of incident angular resolution in high-energy fixed-target collision experiments

A general calculation of the correction to the measured cross section in fixed-target experiments, due to the angular resolution of the incident beam, is carried out. A first-order expression in the incident solid angle ΔΩ is explicity given, and shows that, in the TeV region, angular resolutions as accurate as 10^?1 mrad are required for measurements within the cross-section forward peak.     

On the angular distribution of photonucleons from 16O in the giant resonance region

Irregularities in the energy dependence of the cross section σ₀ and anisotropy coefficient $\text{A}{}_2\text{A}{}_0$ for the ¹⁶O photodisintegration near 21.5 MeV are explained within the framework or pure dipole absorption as the result of the two-channel decay of two interfering resonances with different structure.     

圆屋附近大气折射率结构常数的空间分布

 通过两点温度脉动法,测量了孤立建筑物圆屋附近不同位置的折射率结构常数,对比分析了气象塔8.0,6.0 m高度处的折射率结构常数。结果表明：圆屋附近8.2,8.5,9.0 m高度处的折射率结构常数要比非圆屋附近同高度的结果大;距离圆屋等距离垂直方向的折射率结构常数大于水平方向的测量结果;因此将圆屋附近认为是近地面的假设不成立;圆屋附近温度谱幂率基本符合“－5/3”定律。     

On the production of a lepton pair in the collision of ultrarelativistic neutral particle with nonzero magnetic moment with nuclei

Explicit formulas which describe muon pair production in reaction γν→μ⁺μ⁻ν through neutrino magnetic moment are obtained and used to derive in the leading approximation cross section of muon pair production in νN-scattering due to neutrino magnetic moment. This cross section appears to be proportional to log⁴E_ν. Comparison with experimental data on tridents production provides an upper bound μ_νμ<4×10⁻⁸μ_B, which is approximately two orders of magnitude weaker than that from ν_μe elastic scattering data.     

Atomic structure and collision dynamics with highly charged ions

The research progresses on the investigations of atomic structure and collision dynamics with highly charged ions based on the heavy ion storage rings and electron ion beam traps in recent 20 years are reviewed. The structure part covers test of quantum electrodynamics and electron correlation in strong Coulomb field studied through dielectronic recombination spectroscopy and VUV/x-ray spectroscopy. The collision dynamics part includes charge exchange dynamics in ion-atom collisions mainly in Bohr velocity region, ion-induced fragmentation mechanisms of molecules, hydrogen-bound and van de Waals bound clusters, interference, and phase information observed in ion-atom/molecule collisions. With this achievements, two aspects of theoretical studies related to low energy and relativistic energy collisions are presented. The applications of data relevant to key atomic processes like dielectronic recombination and charge exchanges involving highly charged ions are discussed. At the end of this review, some future prospects of research related to highly charged ions are proposed.     

On constructing the wave function of a quantum particle from its Wigner phase-space distribution function

For a Schrödinger wave function, the part of the phase that depends only on time disappears in the construction of the corresponding Wigner phase-space (quasi)distribution function. Despite this, it can be recovered from the Wigner function using the quantum Hamilton–Jacobi equation. This is demonstrated for three simple cases.