We present the results of the first reduced model simulations of the nonlinear development of the two-plasmon decay instability in an inhomogeneous plasma, including properties of the 3/2 harmonic emission. A sharp increase in radiation and Langmuir turbulence fluctuation levels occurs above a threshold laser intensity that depends on initial fluctuation levels. We study the competition between...

We analyse the reflection of a TM electromagnetic field first on a flat dielectric film and second on a Veselago film with negative refractive index, both films being deposited on a metallic substrat acting as a mirror. An incident harmonic plane wave generates inside a conventional dielectric film a refracted propagating wave and an evanescent wave that does not contribute to reflection on the...

Parametrically-excited surface waves, forced by a repeating sequence of delta-function impulses, are considered within the framework of the Zhang-Viñals model [W. Zhang and J. Viñals, J. Fluid Mech. 336, 301 (1997)]. With impulsive forcing, the linear stability analysis can be carried out exactly and leads to an implicit equation for the neutral stability curves. As noted previously [J. Bechhoe...

A new algorithm for the detection of oscillatory events in the EEG is presented. By estimating autoregressive (AR) models on short segments the EEG is described as a superposition of harmonic oscillators with damping and frequencies varying in time. Oscillatory events are detected, whenever the damping of one or more frequencies falls below a predefined threshold. The algorithm works well for t...

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The new mechanism for obtaining a nonlinear phase shift has been proposed and the schemes are described for its implementation. As it is shown, the interference of two waves with intensity-dependent amplitude ratio coming from the second harmonic generation should produce the nonlinear phase shift. The sign and amount of nonlinear distortion of a beam wavefront is dependent of the relative phas...

Abstract We consider problems based on linear water wave theory concerning the interaction of oblique waves with horizontal cylinders in a fluid consisting of a layer of finite depth bounded above by a free surface and below by an infinite layer of fluid of greater density. For such a situation time-harmonic waves can propagate with two different wavenumbers K and k. The particular problems of ...

Analysis of wave interaction in nonlinear media is a fundamental problem of nonlinear physics. Resonant interaction is especially interesting since it leads to an energy exchange between waves of different carrier frequencies. In a medium without the center of symmetry, quadratic nonlinearity results in parametric three-wave mixing when two waves create a third wave at a combined frequency v3 ­...

Second harmonics have been observed in various magnetospheric waves. Although particle simulations are able to produce the similar features as reported satellite observations, exact physical mechanism for generation of second remains uncovered yet. In this letter, we first give wave equations describing fundamental and via multiscale analysis. Then, apply a kinetic theory approach obtain conduc...

We present a simple but e ective approach to pitch modi cation of speech based on a harmonic model. Building on our time-scaling algorithm [1], pitch modi cation applies to a harmonically coded glottal wave estimate derived via a simple inverse ltering technique [3]. The modi ed glottal wave subsequently serves as input to an LPC vocal tract lter and the pitch-scaled speech is generated. Shape ...