Ambiguities in the partial-wave analysis of pseudoscalar-meson photoproduction

Ambiguities in pseudoscalar-meson photoproduction, arising from incomplete experimental data, have analogs in pion-nucleon scattering. Amplitude ambiguities have important implications for the problems of amplitude extraction and resonance identification in partial-wave analysis. The effect of these ambiguities on observables is described. We compare our results with those found in earlier studies.Comment: 12 pages of text. No figure

RZLINE code modelling of distributed tin targets for laser-produced plasma sources of extreme ultraviolet radiation

Abstract. An integrated model is developed to describe the hydrodynamics, atomic, and radiation processes that take place in extreme ultraviolet (EUV) radiation sources based on a laser-produced plasma with a distributed tin target. The modeling was performed using the RZLINE code—a numerical code for the simulation of EUV emission by hot dense plasmas. The purpose of the simulation is to evaluate the spectral characteristics of the radiation source, conversion efficiency, source size, evaporation rate of the target, energetic, and space distribution of debris (nanoparticles, neutrals, and ions). The advantages of a distributed target in comparison with a single droplet target are also discussed

Investigation of the phase transitions in cesium by the average atom model

Abstract: Using the average atom method (quasizone model) we show that the cesium cold curve has two minimums – the first one is at relatively small densities 0.3 g/cm3and the second one is at higher densities 6.2 g/cm3. The first one leads to the usual critical point characterizing the liquid-vapor phase transition, which is confirmed by experimental data. The reason for the second minimum is connected with s-d transition of valence electron. This leads to a second phase transition with the critical point at temperature 6400 K, density 5.3 g/cm3and pressure approximately 61000 atm. This phase transition takes place in the cesium plasma state. In this degenerate nonideal plasma with mean ion charge 1.5 and density 3 g/cm3jumps in a highly ionized state with mean charge of 3.5 and density 6.5 g/cm3.Note: Research direction:Mathematical modelling in actual problems of science and technic

On the determination of plasma parameters on the integrated spectrum

Abstract: The paper describes a method of determining the temperature and density ranges of plasma on the integrated spectrum. Its application to the experimentally obtained EUV spectrum of pinch iron plasma is demonstrated. We discuss the limitations of the method and degree of correctness of the results.Note: Research direction:Mathematical modelling in actual problems of science and technic