Pattern formation in nonlinear optical cavities, when an advection-like term is present, is analyzed. This term breaks the space inversion symmetry causing the existence of a regime of convective instabilities, where noise-sustained structures can be found, and changing the pattern orientation and the selected wavevector. The concepts of convective and absolute instability, noise-sustained stru...

We present two continuum models A and B to study the convective instability of granular materials subjected to vibrations. We carry out the linear stability analysis for model A and uncover the instability mechanism as a supercritical bifurcation of a bouncing solution. We also explicitly determine the onset of convection as a function of control parameters. The simulations results are in excel...

Our objectives are to use both acoustic remote sensing and in situ profile observations of large amplitude internal waves, together with highly resolved numerical simulation, so as to develop a predictive understanding of their behavior, with application to their generation by flow past topography, their contribution to mass and momentum transport, mixing, modulation of near surface bubble clou...

We perform local numerical experiments to investigate the nonlinear stability of thin, radially-stratified disks. We demonstrate the presence of radial convective instability when the disk is nearly in uniform rotation, and show that the net angular momentum transport is slightly inwards, consistent with previous investigations of vertical convection. We then show that a convectively-unstable e...

For a long time, based on the analysis pertaining to a perfectly charge selective interface, electroconvective instability in concentration polarization was attributed to a nonequilibrium mechanism related to the extended space charge which forms next to that of the electric double layer near the limiting current. More recently, it was shown that imperfect charge selectivity of the interface ma...

A simple model of two vertical modes is constructed and analyzed to reveal the basic instability mechanisms of convectively coupled waves. The main novelty of this model is a convective parameterization based on the quasi-equilibrium concept and simplified for a model of two vertical modes. It hypothesizes 1) the approximate invariance of the difference between saturation moist static energy in...

We consider diffusive nonlinear systems with nonlocal two-points coupling, generally induced by misalignment in optical feedback. We expand the stability analysis in F. Papoff and R. Zambrini [Phys. Rev. Lett. 94, 243903 (2005)] to determine convective and absolute thresholds. Nonlocality leads to different effects in comparison to well-known problems with drift, as the existence of opposite ph...

Absolute and convective instabilities of spirals are investigated using the continuous and the so-called absolute spectrum. It is shown that the nature of transport, induced by an absolute instability, is determined by spectral data of the asymptotic wave trains. The results are applied to core and far-field breakup of spiral waves in excitable and oscillatory media.

The linear hydrodynamic stability of proto–neutron stars (PNSs) is considered taking into account dissipative processes such as neutrino transport and viscosity. We obtain the general instability criteria which differ essentially from the well-known Ledoux criterion used in previous studies. We apply the criteria to evolutive models of PNSs that, in general, can be subject to the various known ...