Biomedical subjects
Publications and source records attributed to A Nepomnyashchy.
The influence of the horizontal component of the temperature gradient on nonlinear regimes of oscillatory Marangoni convection in a real symmetric three-layer system is investigated. The transitions between different flow regimes have been studied. The general diagram of regimes is constructed.
We demonstrate experimentally and theoretically (both analytically and numerically) a new type of spatial soliton: a rotating "propeller" soliton. This is a composite soliton made of a rotating dipole component jointly trapped with a bell-shaped component. We observe as much as 239 degrees of rotation over 13 mm of propagation (6.5 diffraction lengths).
We study linear and nonlinear wave scattering by an optical vortex in a self-defocusing nonlinear Kerr medium. In the linear case, we find a splitting of a plane-wave front at the vortex proportional to its circulation, similar to what occurs in the scattered wave of electrons for the Aharonov-Bohm effect. For larger wave amplitudes, we study analytically and numerically the scattering of a dark-soliton stripe (a nonlinear analog of a small-amplitude wave packet) by a vortex and observe a significant asymmetry of the scattered wave. Subsequently, a wave-front splitting of the scattered wave develops into transverse modulational instability, "unzipping" the stripe into trains of vortices with opposite charges.
We analyze the transverse instability of two-component spatial solitons in a saturable nonlinear medium, in relation to recent experimental observations of spatial vector solitons in photorefractive media. We present the stability analysis for all three realizations: dark-bright, bright-bright, and dark-dark soliton pairs, and demonstrate that both the nonlinearity saturation and incoherent mode interaction can lead to a strong suppression of the soliton transverse instabilities.