RadioAstron space-ground VLBI observations of the pulsar B0950+08, conducted with the 10-m space radio telescope in conjunction with the Arecibo 300-m telescope and Westerbork Synthesis Radio Telescope at a frequency of 324 MHz, were analyzed in orde
r to investigate plasma inhomogeneities in the direction of this nearby pulsar. The observations were conducted at a spacecraft distance of 330,000 km, resulting in a projected baseline of 220,000 km, providing the greatest angular resolution ever achieved at meter wavelengths. Our analysis is based on fundamental behavior of structure and coherence functions. We find that the pulsar shows scintillation on two frequency scales, both much less than the observing frequency; but modulation is less than 100%. We infer that the scattering is weak, but a refracting wedge disperses the scintillation pattern. The refraction angle of this cosmic prism is measured as theta_0=1.1 - 4.4 mas, with the refraction direction being approximately perpendicular to the observer velocity. We show that the observed parameters of scintillation effects indicate that two plasma layers lie along the line of sight to the pulsar, at distances of 4.4 - 16.4 pc and 26 - 170 pc, and traveling in different directions relative to the line of sight. Spectra of turbulence for the two layers are found to follow a power law with the indices gamma_1 = gamma_2 = 3.00 +/- 0.08, significantly different from the index expected for a Kolmogorov spectrum of turbulence, gamma=11/3.
We introduce an application of the Quasi-Gasdynamic method for a solution of ideal magnetohydrodynamic equations in the modeling of compressible conductive gas flows. A time-averaging procedure is applied for all physical parameters in order to obtai
n the quasi-gas-dynamic system of equations for magnetohydrodynamics. Evolution of all physical variables is presented in an unsplit divergence form. Divergence-free evolution of the magnetic field is provided by using a constrained transport method based on Stokes theorem. Accuracy and convergence of this method are verified on a large set of standard 1D and 2D test cases.
We inspect the first-order electron-electron capture scenario for transfer ionization that has been recently formulated by Voitkiv et al. (Phys. Rev. A 86, 012709 (2012) and references therein). Using the multichannel scattering theory for many-body
systems with Coulomb interactions, we show that this scenario is just a part of the well-studied Oppenheimer-Brinkmann-Kramers approximation. Accurate numerical calculations in this approximation for the proton-helium transfer ionization reaction exhibit no appreciable manifestation of the claimed mechanism.
We propose pure quantum parton model of soft interactions. The model is based on soft partons which interact eikonally and locally in a transverse plane. We directly construct S-matrix operator and partons Fock space using developed method of discret
ization of a transverse plane. Counting inelastic states we explicitly derive AGK cancellations and cutting rules from relation between inclusive and exclusive parton distributions. We also discuss black disk behavior from the point of view of our model.
A new type of noise-induced synchronous behavior is described. This phenomenon, called incomplete noise-induced synchronization, arises for one-dimensional Ginzburg-Landau equations driven by common noise. The mechanisms resulting in the incomplete n
oise-induced synchronization in the spatially extended systems are revealed analytically. The different model noise are considered. A very good agreement between the theoretical results and the numerically calculated data is shown.
We report a 1 um continuous wave pumped supercontinuum which extends short of the pump wavelength to 0.65 um. This is achieved by using a 50 W Yb fibre laser in combination with a photonic crystal fibre with a carefully engineered zero dispersion wav
elength. We show that the short wavelength generation is due to a combination of four-wave mixing and dispersive wave trapping by solitons. The evolution and limiting factors of the continuum are discussed.
