arXiv subjects

S. N. Dorogovtsev

Publications and source records attributed to S. N. Dorogovtsev.

94 records · Page 6Linked to original sources

arXiv1998

Avalanche mixing of granular solids in a rotating 2D drum and discrete mapping

Evolution of mixing of granular solids in a slowly rotated 2D drum is considered as a discrete mapping. The rotation is around the axis of the upright drum which is filled partially, and the mixing occurs only at a free surface of a material. The most simple cases that demonstrate clearly the essence of such a type of mixing are studied analytically. We calculate the characteristic time of the mixing and the distribution of the mixed material over the drum.

cond-mat↗

arXiv1998

Nonlinear nonlocal diffusion of magnetic flux in thin type-II superconductors and Josephson junction arrays: Exact solutions

An exact solution of the nonlinear nonlocal diffusion problem is obtained that describes the evolution of the magnetic flux injected into a soft or hard type-II superconductor film or a two-dimensional Josephson junction array. (The magnetic field in vortices is assumed to be perpendicular to the film; the electric field induced by the vortex motion is proportional to the local magnetic induction; flux creep in the hard superconductors under consideration is described by the logarithmic U(j) dependence.) Self-similar flux distributions with sharp square-root fronts are found. The fronts are shown to expand with power law time-dependence. A sharp peak in the middle of the distribution appears in the hard superconductor case.

cond-mat↗

arXiv1997

Gyrotropic Percolation

Spiral (gyrotropic) percolation which is related to the behavior of an electron system in strong magnetic fields is studied. It is shown that the scaling behavior area near the percolation threshold is anomalously narrow. The percolation threshold is higher than in a system with usual isotropic percolation (i.e., it is at higher concentrations of undamaged structure elements). Our old value of the critical exponent of the correlation length is corrected.

cond-mat↗

arXiv1997

Avalanche Mixing of Granular Solids

Mixing of two fractions of a granular material in a slowly rotating two-dimensional drum is considered. The rotation is around the axis of the upright drum. The drum is filled partially, and mixing occurs only at a free surface of the material. We propose a simple theory of the mixing process which describes a real experiment surprisingly well. A geometrical approach without appealing to ideas of self-organized criticality is used. The dependence of the mixing time on the drum filling is calculated. The mixing time is infinite in the case of the half-filled drum. We describe singular behaviour of the mixing near this critical point.

cond-mat↗