Resonant scattering of ions on charged dust particles

Resonant scattering ("scattering through waves") of ions on dust particles in plasmas is considered in the framework of the kinetic theory which consistently takes into account ion-dust collisions and dust charge fluctuations. Resonance with low frequency dusty plasma modes can enhance the ion-dust scattering cross section and the ion drag force on dust particles.     

Internal bremsstrahlung of strongly interacting charged particles

A universal theoretical model intended for calculating internal-bremsstrahlung spectra is proposed. In this model, which can be applied to describing nuclear decays of various type (such as alpha decay, cluster decay, and proton emission), use is made of realistic nucleus–nucleus potentials. Theoretical internal-bremsstrahlung spectra were obtained for the alpha decay of the ²¹⁴Po nucleus, as well as for the decay of the ²²²Ra nucleus via the emission of a ¹⁴C cluster and for the decay of the ¹¹³Cs nucleus via proton emission, and the properties of these spectra were studied. The contributions of various regions (internal, subbarrier, and external) to the internal-bremsstrahlung amplitude were analyzed in detail. It is shown that the contribution of the internal region to the amplitude for internal bremsstrahlung generated in nuclear decay via proton emission is quite large, but that this is not so for alpha decay and decay via cluster emission. Thus, a process in which strong interaction of nuclear particles affects the internal-bremsstrahlung spectrum if found.     

Neutron emission under particular nonequilibrium conditions from Pd and Ti electrolytically charged with deuterium

Summary We report on neutron emission in palladium and titanium electrolitically charged with deuterium. The detection of neutrons is observed after thermal treatment of the electrode. In the hypothesis that neutrons came from cold fusion processes, we estimate a fusion rate as high as 1.3·10⁻²¹ fusions/deuteron pair/second.     

Energy loss straggling of fast charged particles

Energy loss straggling of fast charged particles colliding with atoms have been considered in the eikonal approximation. The result is represented in the form of the Fano formula with a nonperturbative correction. The known nonperturbative Titeica formula (which is transformed to the Fano formula when perturbation theory is applicable) is obtained only under certain approximations in eikonal calculations. It has been shown that straggling calculated with allowance for nonperturbative effects at large charges of the projectile can be significantly different (by an order of magnitude) from the results obtained by Titeica, Fano, and Bohr. Energy loss straggling of fast highly charged ions on hydrogen and copper atoms have been calculated. The latter results are compared to experimental data.     

Multiple ionization processes involving fast charged particles

This review is devoted to certain aspects of the theory of multiple ionization of a quantum target by a fast charged particle. Atoms and molecules, and their ions as well, are considered as targets, while electrons and protons are considered as projectiles. Special attention is paid to the effective charge approximation while constructing continuum wave functions for several charged fragments in the exit channel of the reaction. Theoretical calculations of differential and total cross sections of various multiple ionization processes are presented and, where possible, comparison of the results of these calculations with experimental data is carried out.     

Negative hydrogen-ion neutralization in collisions with fast highly charged ions

The neutralization of negative hydrogen ions is considered for collisions with fast multicharged ions (including relativistic collision velocities) by means of an approach that gives a simple analytic expression for the neutralization cross section in the parameter region where the Born approximation is inapplicable. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 42, No. 1, pp. 87–95, January, 1999.     

On the energy losses of fast charged particles

The energy losses of fast charged particles colliding with atoms have been considered in the eikonal approximation. It has been shown that the nonperturbative contribution to the effective stopping from the region of the intermediate impact parameters (comparable with the characteristic sizes of the electron shells of the target) not only can be significant as compared to shell corrections to the Bethe-Bloch formula (usually considered in the first order of perturbation theory), but also can provide significant (up to 50%) corrections to this formula.     

Propagation of fast charged particles along a nanotube

The results obtained by investigating the motion of fast charged particles in a nanotube along its axis are presented. It is shown that dynamical chaos may arise when a positively charged particle moves along the axis of a nanotube.     

Physics of collective attraction of negatively charged dust particles

A physical interpretation is proposed for the collective attraction of dust particles, leading to pairing of likely (negatively) charged dust particles, the formation of dust molecules, and the emergence of other complexes containing a large number of dust particles (in the limit, dust plasma crystals). The value of the spacing between particles in such dust structures estimated on the basis of the proposed mechanism of attraction corresponds to the observed interparticle distances in the crystal lattices of recently discovered plasma-dust crystals. The proposed mechanism may form the basis for interpreting various phenomena frequently observed in dusty plasmas.     

Interactions of charged dust particles in clouds of charges

Two charged dust particles inside a cloud of charges are considered as Debye atoms forming a Debye molecule. Cassini coordinates are used for the numerical solution of the Poisson-Boltzmann equation for the charged cloud. The electric force acting on a dust particle by the other dust particle was determined by integrating the electrostatic pressure on the surface of the dust particle. It is shown that attractive forces appear when the following two conditions are satisfied. First, the average distance between dust particles should be approximately equal to two Debye radii. Second, attraction takes place when similar charges are concentrated predominantly on the dust particles. If the particles carry a small fraction of total charge of the same polarity, repulsion between the particles takes place at all distances. We apply our results to the experiments with thermoemission plasma and to the experiments with nuclear-pumped plasma.     

Theory of mach cones in magnetized dusty plasmas with strongly correlated charged dust grains

A theory for the formation of Mach cones in a magnetized dusty plasma with strongly correlated charged dust grains has been presented. We use the electron and ion susceptibilities for weakly correlated magnetized electrons and ions as well as the strongly correlated unmagnetized dust grain susceptibilities which are obtained by means of the quasilocalized charge approximation and a generalized hydrodynamic model. The plasma dielectric response of the present system reveals the parametric regimes for which Mach cones in a strongly coupled laboratory dusty magnetoplasma can be formed. We suggest conducting experiments in radiofrequency dusty plasma discharges with superconducting magnets for verifying the theoretical prediction of Mach cones that is made herein.     

Self-sustained oscillations in a plasma-wall system with strongly inhomogeneous diffusion of charged particles

A simple system with a hydrogen plasma confined by a magnetic field parallel to the bounding material wall is considered. The charged particles diffuse out of the plasma, recombine on the wall and return into the plasma volume as neutrals, which are ionized by electrons. It is demonstrated that macroscopic self-sustained oscillations are an intrinsic feature of such a system if the diffusion coefficient of charged particles is strongly inhomogeneous in the plasma.     

Channeling of fast charged and neutral particles in nanotubes

We present a theory to describe the propagation of relativistic charged particles, X-rays and thermal neutrons through straight or slightly bent nanotubes and calculated the spectra of electromagnetic radiation accompanying the channeling of charged particles.     

带电粒子与二维强耦合尘埃等离子体的相互作用

当船在水中自由滑行时，一方面会在水面产生一个“V”型的尾波，另一方面它会由于水的摩擦而不断减速．有意思的是，当带电粒子在二维强耦合尘埃等离子体表面飞行时，也会发生类似的现象．     

Confinement of charged dust particles by a hybrid-type electric curtain

The hybrid-type electric curtain (HTEC) comprises a planar electric curtain and a perpendicular planar condenser. Serial cylindrical electrodes are supplied with AC voltage, whereas the condenser is fed with DC voltage. HTEC allows for better control of the particle position shift in space. The particle oscillation path within the hybrid curtain has been photographically analysed. The changing particle path was recorded according to a DC changing voltage value and a constant AC voltage value. The aim of the paper is to describe a successful method that enables one to experimentally determine the region where the particle can be stably oscillated.     

带电粒子与二维强耦合尘埃等离子体的相互作用

当船在水中自由滑行时,一方面会在水面产生一个“V”型的尾波,另一方面它会由于水的摩擦而不断减速.有意思的是,当带电粒子在二维强耦合尘埃等离子体表面飞行时,也会发生类似的现象.     

Effects of polarization force and nonthermal ions on dust-acoustic (DA) shock waves in a strongly coupled dusty plasma with positively charged dust

The nonlinear propagation of the dust-acoustic (DA) waves in a strongly coupled dusty plasma containing Maxwellian electrons, nonthermal ions, and positively charged dust is theoritically investigated by a Burgers equation. The effects of the polarization force (which arises due to the interaction between electrons and highly positively charged dust grains) and nonthermal ions are studied. DA shock waves are found to exist with positive potential only. It represents that the strong correlation among the charged dust grains is a source of dissipation, and is responsible for the formation of DA shock waves. The effects of polarization force and nonthermal ions significantly modified the basic features of DA shock waves in strongly coupled dusty plasma.     

Ionization energy losses of fast charged particles produced in matter

Ionization energy losses of an ultrarelativistic electron produced in matter are considered. The interference of the proper Coulomb field of the product particle and the electromagnetic wave that this particle emits is shown to be significant at impact-parameter values that make a dominant contribution to the ionization energy losses. The effect is shown to exert virtually no influence on the ionization energy losses of the particle.     

Ionization losses of fast charged particles in an anisotropic medium

The energy losses of fast charged particles in anisotropic media are investigated. The macroscopic Maxwell equations are used to find the electromagnetic field of particles moving according to a given law in an anisotropic medium. A solution in quadratures is obtained for the energy loss of a charge moving at an angle to the optical axis of a weakly anisotropic uniaxial crystal; the result is in the form of a correction to the ionization losses in an isotropic medium. In the case of a medium consisting of anisotropic oscillators, an analytic formula is obtained for the correction: It is inversely proportional to the square of the velocity at particle velocities much less than the velocity of light and tends to zero for ultrarelativistic particles.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 14–19, January, 1978.Finally, it remains to thank O. B. Evdokimov for formulating the problem and for useful discussions.