We put forward the existence of a rich variety of fully stationary vortex structures, termed H clusters, made of an increasing number of vortices nested in paraxial wave fields confined by trapping potentials. However, we show that the constituent vortices are globally linked, rather than products of independent vortices. Also, they always feature a monopolar global wave front and exist in nonl...

Elementary excitations of vortices placed in one component of a binary mixture of Bose-Einstein condensates have been studied using perturbative and numerical solutions of the linearised equations for excitations, and numerical simulation of the coupled Gross-Pitaevskii equations. Two distinct instabilities originating from resonances of the excitations have been found. One leads to the vortex ...

A supersonic combustor was experimentally investigated using both conventional instrumentation and laser-based diagnostics. Planar laser-induced fluorescence (PLIF) imaging of OH was used in the main section of the combustor to examine flameholding and flame propagation during a series of evaluations at conditions simulating Mach-5.5 flight. Parameters of interest in this study included the ang...

This paper reports on our research in developing a micro power generation system based on gas turbine engine and piezoelectric converter. The micro gas turbine engine consists of a micro combustor, a turbine and a centrifugal compressor. Comprehensive simulation has been implemented to optimal the component design. We have successfully demonstrated a silicon-based micro combustor, which consist...

We present a mean-field theory numerical study of Tkachenko waves of a vortex lattice in trapped atomic Bose-Einstein condenstates. Our results show remarkable qualitative and quantitative agreement with recent experiments at the Joint Institute for Laboratory Astrophysics. We extend our calculations beyond the conditions of the experiment, probing deeper into the incompressible regime where we...

We predict theoretically and generate in a photorefractive crystal two-dimensional self-trapped periodic waves of different symmetries, including vortex lattices-patterns of phase dislocations with internal energy flows. We demonstrate that these nonlinear waves exist even with anisotropic nonlocal nonlinearity when the optically-induced periodic refractive index becomes highly anisotropic, and...

We introduce a novel class of spatially localized self-trapped ringlike singular optical beams in nonlinear media, the so-called azimuthons, which appear due to a continuous azimuthal deformation of vortex solitons. We demonstrate that the azimuthons are characterized by two independent integer indices, the topological charge m and the number N of the intensity peaks along the ring. Each solito...

We demonstrate both experimentally and theoretically that a colloidal sphere trapped in a static optical tweezer does not come to equilibrium, but rather reaches a steady state in which its probability flux traces out a toroidal vortex. This nonequilibrium behavior can be ascribed to a subtle bias of thermal fluctuations by nonconservative optical forces. The circulating sphere therefore acts a...

Homeotropic nematic liquid crystal cells with a photosensitive wall and negative dielectric anisotropy exhibit, under the influence of local illumination, stable vortexes with swirling arms that are trapped at the illuminated area. Close to the Fréedericksz transition an amplitude equation is derived, which allows us to understand the origin of the induced vortex and the competition between the...