Observation of dielectronic satellites in the K-spectrum of argon ions in plasma produced by femtosecond laser pulses

The satellite structure of 1s2p ^1,3 P ₁-1s ²¹ S ₀ lines of the He-like argon ion in plasma produced by a 45-fs laser pulse in a gas-jet cluster target is measured with a high spectral resolution. Radiation transitions 2p → 1s from autoionizing states (AISs) are detected for ions ranging from Li-like to F-like. The spectrum observed is theoretically simulated with the use of the spectroscopic data for the AISs of multicharged ions obtained within the multiconfiguration relativistic Hartree-Fock method. Good agreement with experimental data is obtained when the main population channels of these states are taken into account for typical values of cluster-target plasma parameters.     

Production of heavy nuclei in the interaction of <Superscript>7</Superscript>Li ions with copper nuclei at an energy of 35 MeV per nucleon

The absolute values of the cross sections for the production of target fragments in the interaction of copper with ⁷Li ions at an energy of 35 MeV per nucleon were measured. The measurements were performed by recording the yields of radioactive nuclear residues with the aid of a semiconductor detector from ultrapure germanium. The charge and isobaric distributions in the mass-number range 22–69 amu were used to deduce the mass yield of reaction products and to calculate the total interaction cross section. The results are presented that were derived from a comparison with data obtained for ¹²C + Cu reactions and with estimates based on theoretical models.     

On the dynamic properties of “elastic” interactions between wave solitons consisting of a few field oscillation cycles

By the numerical simulation of the dynamics of the optical circularly polarized field in the Kerr-type medium, it has been shown that the binary collisions between wave solitons consisting of a few field oscillation cycles with respect to their energy characteristics exhibit the properties of the collisions of Schrödinger solitons. The corresponding spectral characteristics change according to the conservation of the soliton-like structure of the envelop. In dependence on the absolute difference of the field phases, there are three different interaction regimes: the passage of one structure through another, their repulsion, and the exact replication of one initial wave structure by another.     

Expansion parameter of the vertex function in the two-dimensional approximation of quantum electrodynamics

The contribution of the fifth-order diagrams to the vertex function of an electron in a strong magnetic field B B₀ = m²/e = 4.41·10¹³ G is calculated. It is shown that the diagram with electron loop is dominant; this leads to a linear dependence of the form factor f⁽⁵⁾(t) on the field. Comparison with the main contribution from the simplest triangle diagram shows that perturbation theory in. becomes invalid in fields with induction 10^17–18 G.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 126–129, September, 1978.     

Emission of neutrinos by alternating fields

It is supposed that the effective Lagrangian of interaction of a magnetic field with a neutrino can be written in the form $$L_{eff} = \frac{{G_{\mathbf{\gamma }} }}{{m_W^2 }} \frac{{\partial ^2 A^\mu }}{{\partial x^v \partial x_v }}[\bar \Psi _v {\mathbf{\gamma }}_\mu (1 + {\mathbf{\gamma }}^5 )\Psi _v ].$$ Formulas are obtained for the emission of neutrinos by alternating fields. In particular, neutrino synchrotron emission and neutrino emission in the case of collision of two classical charges are considered. Arguments are presented that this mechanism can make a contribution to the neutrino luminosity of stars.     

Self-action of Bessel wave packets in a system of coupled light guides and formation of light bullets

The self-action of two-dimensional and three-dimensional Bessel wave packets in a system of coupled light guides is considered using the discrete nonlinear Schrödinger equation. The features of the self-action of such wave fields are related to their initial strong spatial inhomogeneity. The numerical simulation shows that for the field amplitude exceeding a critical value, the development of an instability typical of a medium with the cubic nonlinearity is observed. Various regimes are studied: the self-channeling of a wave beam in one light guide at powers not strongly exceeding a critical value, the formation of the “kaleidoscopic” picture of a wave packet during the propagation of higher-power radiation along a stratified medium, the formation of light bullets during competition between self-focusing and modulation instabilities in the case of three-dimensional wave packets, etc. In the problem of laser pulse shortening, the situation is considered when the wave-field stratification in the transverse direction dominates. This process is accompanied by the self-compression of laser pulses in well enough separated light guides. The efficiency of conversion of the initial Bessel field distribution to two flying parallel light bullets is about 50%.     

Spatial Transformations of Atoms

Russian Physics Journal - On the basis of fundamental probabilistic arguments, a theory of spatial transitions of atoms in configurations with number of spatial dimensions D = 1, 2, and 3 is...