Search results for "Parametric statistics"
showing 10 items of 354 documents
A study of the potential influence of frame coolant on HCLL-TBM nuclear response
2007
Abstract Within the European Fusion Technology Programme, the Helium-Cooled Lithium Lead (HCLL) breeding blanket concept is one of the two EU lines to be developed for a long term fusion reactor, in particular with the aim of manufacturing a test blanket module (TBM) to be implemented in ITER. The HCLL-TBM is foreseen to be located in an ITER equatorial port, being housed inside a steel-supporting frame, actively cooled by pressurized water. This supporting frame has been designed to house two different TBMs providing two cavities separated by a dividing plate 20 cm thick. As the nuclear response of HCLL-TBM could vary with the supporting frame configuration and composition, a parametric st…
Generalized complex Swift-Hohenberg equation for optical parametric oscillators
1997
A generalized complex Swift-Hohenberg equation including diffraction and nonlinear resonance terms is derived for spatially extended nondegenerate optical parametric oscillators (OPOs) with flat end mirrors. For vanishing pump detuning this equation becomes the complex Swift-Hohenberg (SH) equation valid also for lasers. Nevertheless the similarities between OPOs and lasers are limited, since the diffractive character of OPOs is lost when the diffraction coefficients of signal and idler fields are equal. This manifests, e.g., in the absence of advection by traveling waves (TWs), a clear difference with lasers. When pump detuning is nonzero a nonlinear resonance develops, as it occurs in deg…
Role of pump diffraction on the stability of localized structures in degenerate optical parametric oscillators.
2000
We show that the stability range of localized structures (LS's) in the form of minimum size phase domains in degenerate optical parametric oscillators is enhanced by increasing the diffraction of the pump wave. Pump diffraction enhances spatial oscillations of decaying tails of domain boundaries, whereas spatially oscillating (weakly decaying) tails prevent the collapse of LS's, enhance their stability range, and allow the existence of more complex LS's in the form of molecules.
Parametric Excitation of Density Waves in Drifting Electron-Hole Plasmas
1972
The effect of the electronic drift velocity on the conditions for parametric excitation in electron-hole plasmas is investigated in the two-mode approximation using a Vlasov-equations approach. The results show that when the electronic drift velocity approaches the phase velocity of the lower frequency mode of the plasma, a considerable lowering of the threshold for the onset of parametric excitation occurs, thus resulting in more favorable conditions for experimental observation of the process. The dependence of the threshold on other relevant physical parameters involved, such as the electron-to-hole mass and temperature ratios, is also investigated.
Bright and dark optical solitons in fiber media with higher-order effects
2002
We consider N-coupled higher-order nonlinear Schrodinger (N-CHNLS) equations which govern the simultaneous propagation of N optical fields in fiber media with higher-order effects. Bright and dark soliton solutions are derived using Hirota bilinear method for the general cross-coupling ratio between the parameters of self-phase modulation and cross-phase modulation effects. By means of coupled amplitude-phase formulation also, similar kind of dark soliton solutions are obtained. It is found that the parametric conditions for the simultaneous propagation of N dark solitons from both the methods are the same.
Modelling uncertainties in phase-space boundary integral models of ray propagation
2020
Abstract A recently proposed phase-space boundary integral model for the stochastic propagation of ray densities is presented and, for the first time, explicit connections between this model and parametric uncertainties arising in the underlying physical model are derived. In particular, an asymptotic analysis for a weak noise perturbation of the propagation speed is used to derive expressions for the probability distribution of the phase-space boundary coordinates after transport along uncertain, and in general curved, ray trajectories. Furthermore, models are presented for incorporating geometric uncertainties in terms of both the location of an edge within a polygonal domain, as well as …
Observation of collapse arrest in pure kerr media sustained by a parametric interaction
2013
We demonstrate a parametric interaction based on four wave mixing that can arrest the collapse and stabilize solitary propagation in a pure Kerr material by controlling the wavelength of the interacting beams.
Propagation, Stability and Interactions of Novel Three-Wave Parametric Solitons
2006
International audience; We found a new class of analytic soliton solutions that describe the parametric wave mixing of optical pulses in quadratic nonlinear crystals. We analyze the stability properties, interactions and collisions of these solitons.
Dark- and bright-rogue-wave solutions for media with long-wave–short-wave resonance
2014
5 pags.; 5 figs.; PACS number(s): 46.40.−f, 47.20.Ky, 47.35.−i, 47.52.+j
X-shaped space-time coherence in optical parametric generation
2007
We study the spatiotemporal coherence properties of superfluorescence radiation generated in optical parametric amplification of quantum noise. We show that the angular dispersion properties of the spatiotemporal spectra, measured in different phase-matching conditions, lead to a clear X-shaped structure of the mutual correlation function of the radiation. Within a statistical picture, we interpret the generated superfluorescence as a stochastic “gas” of quasistationary modes characterized by a skewed correlation in the spatiotemporal domain, with characteristics similar to linear and nonlinear X waves not describable within a separable approach in space and time.