Phase transition in compressible Ising systems at fixed volume

Using a Ginzburg-Landau model, we study the phase transition behavior of compressible Ising systems at constant volume by varying the temperature $T$ and the applied magnetic field $h$. We show that two phases can coexist macroscopically in equilibrium within a closed region in the $T$-$h$ plane. It occurence is favored near tricriticality. We find a field-induced critical point, where the correlation length diverges, the difference of the coexisting two phases and the surface tension vanish, but the isothermal magnetic susceptibility does not diverge in the mean field theory. We also investigate phase ordering numerically.Comment: 13 figure

Solar flare and CME predictions using numerical MHD simulations

According to observational and theoretical data the solar flare radiation and coronal mass ejection(CME) are manifestations of the same explosive process, which takes place high in the solar corona. In some solar flares one of these manifestations can be weak and can not be observed, in other flares both of these manifestations are present. CMEs are the most important cause of substorm appearances in the magnetosphere. For solar flare and CME predictions, it is need to have information about main processes of these explosive phenomena and to estimate the possibility of their occurrences. The energy for solar flare can be accumulated in a current sheet. For MHD simulation of this process the program PERESVET is developed that uses observed distributions of magnetic field on the photosphere as the boundary conditions. The MHD simulation showed, that the current sheet can be vertical, horizontal, or inclined to some angles to the photosphere depending on the magnetic field distribution on the photosphere and its evolution. The vertical current sheet can produce the CME, because the magnetic tension force accelerates plasma from the Sun. The CME prognosis is based on information about the position of current sheet in the solar corona

Obliquely backscattered Thomson scattering system on the compact helical system

A Thomson scattering system with an obliquely backscattered configuration with a novel, high throughput collection system was developed and tested on a plasma confinement device, the compact helical system. It can yield the full profiles of electron temperature and density along a major radius with the spatial resolution ranging from 1.5 to 4 cm at a repetition rate of up to 250 Hz

Statistical properties of spectral fluctuations for a quantum system with infinitely many components

Extending the idea formulated in Makino {\it{et al}}[Phys.Rev.E {\bf{67}},066205], that is based on the Berry--Robnik approach [M.V. Berry and M. Robnik, J. Phys. A {\bf{17}}, 2413], we investigate the statistical properties of a two-point spectral correlation for a classically integrable quantum system. The eigenenergy sequence of this system is regarded as a superposition of infinitely many independent components in the semiclassical limit. We derive the level number variance (LNV) in the limit of infinitely many components and discuss its deviations from Poisson statistics. The slope of the limiting LNV is found to be larger than that of Poisson statistics when the individual components have a certain accumulation. This property agrees with the result from the semiclassical periodic-orbit theory that is applied to a system with degenerate torus actions[D. Biswas, M.Azam,and S.V.Lawande, Phys. Rev. A {\bf 43}, 5694].Comment: 6 figures, 10 page