Possible classification of the self-oscillatory spouting regimes of plane vertical submerged jets of a heavy fluid

New results of an experimental investigation of self-oscillatory regimes of plane vertical jet spouting from beneath the free surface of a heavy incompressible fluid are discussed. The experiments were performed on a setup with discharge over a weir. The range of dimensionless jet submergence values on which bifurcation change of spouting regime is observable is studied. It is established that on the Froude number and dimensionless jet submergence ranges considered in the study six characteristic spouting regimes differing in free surface shape and self-oscillation frequency can exist. It is shown that these regimes can be subdivided into three typical groups with respect to the dependence of the self-oscillation period on the jet flow rate. A dimensionless parameter that makes it possible to identify the boundaries of the bifurcation change in spouting regimes is obtained for each of these groups. For certain spouting regimes without the formation of free jets numerical calculations are carried out using the STAR-CD software package; the calculated results are in good agreement with experimental data.     

Nuclear reactions triggered by laser-accelerated high-energy ions

A technique is suggested for triggering nuclear reactions by accelerating ions with a powerful ultrashort laser pulse in a plasma. The underlying idea of the suggested compact “reactor” is utilization of high-energy ions accelerated by the charge-separation electrostatic field in the direction perpendicular to the laser beam axis in a gas-filled capillary. Accelerated ions with energies of several MeV penetrating the target from the inside surface of a channel give rise to nuclear reactions which can be used to create a compact source of fast neutrons and neutrons of intermediate energies for generating various (short-and long-lived, light and heavy) isotopes, for generating gamma radiation over a broad energy range, for making sources of light ion and induced radioactivity. The yield of the corresponding nuclear reactions as a function of the laser beam parameters has been investigated. The suggested technique for triggering nuclear reactions provides a practical tool for studies of nuclear transformation on the pico-and nanosecond scales, which cannot be achieved using other methods. Zh. éksp. Teor. Fiz. 115, 2080–2090 (June 1999)     

Fayans Functional: Self-Consistent Description of Isospin Excitations

Physics of Atomic Nuclei - The energy density functional proposed earlier by Fayans and his coauthors is modified in such a way as to apply it in fully self-consistent calculations of isobaric...     

Results of Microscopic Self-Consistent Theory of Quasiparticle—Phonon Interaction in Nuclei

Physics of Atomic Nuclei - A self-consistent approach in the problem of taking into account quasiparticle-phonon interaction provides a high predictive power and is free from adjustable parameters...     

Neutrino flavor relaxation or neutrino oscillations?

We propose the new mechanism of neutrino flavor relaxation to explain the experimentally observed changes of initial neutrino flavor fluxes. The test of neutrino relaxation hypothesis is presented using the data of modern reactor, solar, and accelerator experiments. The final choice between the standard neutrino oscillations and the proposed neutrino flavor relaxation model can be done in future experiments.     

Modeling of an inhomogeneous coating of an elastic cylinder with given sound-reflecting properties

This paper considers the inverse problem of determining the inhomogeneity laws of the coating of an elastic cylinder that provide minimum reflection of a plane acoustic wave in a particular angular sector and in a given frequency range. A functional that expresses the reflection intensity is constructed by direct solution of the direct problem, and an algorithm for minimizing this functional is proposed. Analytical expressions describing the mechanical parameters of the inhomogeneous coating are obtained.     

Phonon–particle coupling effects in odd–even double mass differences of magic nuclei

It has been proposed to use the formation of a magnetized plasma of laser-accelerated ions and electrons at the irradiation of the curved surface of the inner cavity of the target by a petawatt laser pulse to initiate a neutronless nuclear reaction of protons with boron nuclei. The possibility of an additional increase in the intensity of the reaction owing to the compression of the plasma at the irradiation of the outer surface of the target by a second terawatt laser pulse synchronized in time with the plasma-forming pulse has been discussed. The parameters of laser pulses and a target have been determined at which the ignition of a pB plasma occurs; i.e., the energy released in reactions is equal to the energy of the plasma.     

Phonon–particle coupling effects in the single-particle energies of semi-magic nuclei

A method is presented to evaluate the particle–phonon coupling (PC) corrections to the single-particle energies in semi-magic nuclei. In such nuclei, always there is a collective low-lying 2⁺ phonon, and a strong mixture of single-particle and particle–phonon states often occurs. As in magic nuclei the so-called g _L ² approximation, where g _L is the vertex of the L-phonon creation, can be used for finding the PC correction δΣ^PC(ε) to the initial mass operator Σ₀. In addition to the usual pole diagram, the phonon “tadpole” diagram is also taken into account. In semi-magic nuclei, the perturbation theory in δΣ^PC(ε) with respect to Σ₀ is often invalid for finding the PC-corrected single-particle energies. Instead, the Dyson equation with the mass operator Σ(ε) = Σ₀ + δΣ^PC(ε) is solved directly, without any use of the perturbation theory. Results for a chain of semi-magic Pb isotopes are presented.