This paper presents a comprehensive analytical study of temporal modulation instabilities in a finite, nonlinear, dispersive medium in which two counterpropagating pump beams interact through a Kerr-type nonlinearity. The analysis includes selfand cross-phase modulations, group-velocity dispersion, four-wave mixing, and reflections occurring at the two facets of the dispersive Kerr medium. The ...

Active control of thermoacoustic instabilities in continuous premixed combustion processes is being increasingly investigated for operating at lean low NOX conditions. Recently, we have developed a model-based approach for active control design which accounts for the underlying acoustics, heat release dynamics, and sensor and actuator dynamics. While this model captures a number of the dominant...

The impact of intrinsic combustion instabilities is studied for lean premixed hydrogen flames by means a series simulations at different equivalence ratios [0.4-1.0], unburned temperatures [298K-700K], and pressures [1bar-20bar]. In addition to the Darrieus-Landau, or hydrodynamic, instability, are prone thermodiffusive instabilities, which lead significant flame front wrinkling chaotic process...

The success of the neutrino mechanism of core-collapse supernovae relies on the supporting action of two hydrodynamic instabilities: neutrino-driven convection and the standing accretion shock instability (SASI). Depending on the structure of the stellar progenitor, each of these instabilities can dominate the evolution of the gain region prior to the onset of explosion, with implications for t...

We consider the existence, stability and dynamics of the nodeless state and fundamental nonlinear excitations, such as vortices, for a quasi-two-dimensional polariton condensate in the presence of pumping and nonlinear damping. We find a series of interesting features that can be directly contrasted to the case of the typically energy-conserving ultracold alkali-atom Bose-Einstein condensates (...

ZZ Ceti stars exhibit small amplitude photometric pulsations in multiple gravity modes. As the stars cool their dominant modes shift to longer periods. We demonstrate that parametric instability limits overstable modes to amplitudes similar to those observed. In particular, it reproduces the trend that longer period modes have larger amplitudes. Parametric instability is a form of resonant 3-mo...

Abstract Although tremendous achievements have been made toward inertial confinement fusion, laser plasma instabilities (LPIs) remain to be an inevitable problem for current drive schemes. To mitigate these instabilities, significant efforts paid produce high-power broadband ultraviolet lasers. However, no practical scheme has demonstrated up now efficient triple-frequency conversion of laser. ...