Search results for "waves"
showing 10 items of 1766 documents
Families of rational solutions to the KPI equation of order 7 depending on 12 parameters
2017
International audience; We construct in this paper, rational solutions as a quotient of two determinants of order 2N = 14 and we obtain what we call solutions of order N = 7 to the Kadomtsev-Petviashvili equation (KPI) as a quotient of 2 polynomials of degree 112 in x, y and t depending on 12 parameters. The maximum of modulus of these solutions at order 7 is equal to 2(2N + 1)2= 450. We make the study of the patterns of their modulus in the plane (x, y) and their evolution according to time and parameters a1, a2, a3, a4, a5, a6, b1, b2, b3, b4, b5, b6. When all these parameters grow, triangle and ring structures are obtained.
Rational solutions to the KPI equation of order 7 depending on 12 parameters
2018
We construct in this paper, rational solutions as a quotient of two determinants of order 2N = 14 and we obtain what we call solutions of order N = 7 to the Kadomtsev-Petviashvili equation (KPI) as a quotient of 2 polynomials of degree 112 in x, y and t depending on 12 parameters. The maximum of modulus of these solutions at order 7 is equal to 2(2N + 1) 2 = 450. We make the study of the patterns of their modulus in the plane (x, y) and their evolution according to time and parameters a1, a2, a3, a4, a5, a6, b1, b2, b3, b4, b5, b6. When all these parameters grow, triangle and ring structures are obtained.
Nonlinear Kelvin waves on a quantized vortex line in superfluid helium
2013
In this paper we show an exact solution (Kelvin wave) of an approximated dynamical equation for a quantized vortex line in helium superfluid at finite temperature. It is shown that the applied heat flux interacts with the vortex line, and the amplitude of the Kelvin wave can grow (the so-called Donnelly instability) or decrease according with the mutual direction between heat flux and wave vector.
Measurement of high order Kerr refractive index of major air components
2009
International audience; We measure the instantaneous electronic nonlinear refractive index of N2 , O2 , and Ar at room temperature for a 90 fs and 800 nm laser pulse. Measurements are calibrated by post-pulse molecular alignment through a polarization technique. At low intensity, quadratic coefficients n2 are determined. At higher intensities, a strong negative contribution with a higher nonlinearity appears, which leads to an overall negative nonlinear Kerr refractive index in air above 26 TW/cm2 .
Theory of spontaneous polarization and birefringence in the tetragonal phase of KNbO3
1995
Abstract The microscopic mechanism of optical anisotropy in the tetragonal phase of KNbO3 is discussed taking account of the dipole-dipole effect due to the ionic and electronic polarizations of the crystal and the spontaneous Kerr effect. The last effect is a cause of the strong local field acting on the constituent ions. For the spontaneous polarization we use only the first effect. It is found that the birefringence and the spontaneous polarization are in good agreement with the experimental data.
Incoherent solitons and condensation processes
2006
International audience; We study the nonlinear interaction of partially incoherent nonlinear optical waves. We show that, in spite of the incoherence of the waves, coherent phase effects may play a relevant role during the propagation, in contrast with the usual wave turbulence description of the interaction. These nonlinear phase effects may lead the system to unexpected processes of self-organization, such as condensation, or incoherent soliton generation in instantaneous response nonlinear media. Such self-organization processes may be characterized by a reduction of the non-equilibrium entropy, which violates the Boltzmann's H-theorem of entropy growth inherent to the wave turbulence th…
Measurement of high order Kerr refractive index of major air components: erratum
2010
A clarification is missing concerning the high order Kerr non-linearities deduced from our experimental data published in [Opt. Express 17, 13429-13434 (2009)]. Here, we rectify this omission by making explicit the distinction between cross-Kerr and Kerr effects, and by extrapolating the value of the nonlinear refractive index for the last effect. Since the occurrence of sign inversion in the Kerr effect is not affected, the overall report in [Opt. Express 17, 13429-13434] remains valid.
Erratum: “Searches for Gravitational Waves from Known Pulsars at Two Harmonics in 2015–2017 LIGO Data” (2019, ApJ, 879, 10)
2019
Two analysis errors have been identified that affect the results for a handful of the high-value pulsars given in Table 1 of Abbott et al. (2019). One affects the Bayesian analysis for the five pulsars that glitched during the analysis period, and the other affects the 5n-vector analysis for J0711-6830. Updated results after correcting the errors are shown in Table 1, which now supersedes the results given for those pulsars in Table 1 of Abbott et al. (2019). Updated versions of figures can be seen in Figures 1-4. Bayesian analysis.-For the glitching pulsars, the signal phase evolution caused by the glitch was wrongly applied twice and was therefore not consistent with our expected model of…
Incidence Angle Diversity on L-Band Microwave Radiometry and Its Impact on Consistent Soil Moisture Retrievals
2021
Incidence angle diversity of space-borne L-band radiometers needs to be taken into account for a consistent estimation of surface soil moisture (SM). In this study, the Land Parameter Retrieval Model (LPRM) is applied to SMOS brightness temperatures to calibrate the effective scattering albedo (w) and the soil roughness (h 1 ) parameter against ERA5-land SM. The analysis is carried out for SMOS data at three different incidence angles ( 32.5±5∘, 42.5±5∘ and 52.5±5∘ ) focusing in 2016 on the three main land cover types of the Iberian Peninsula according to the Climate Change Initiative (agricultural, forest and grassland). The parameterization shows an increasing trend of w and h 1 with rise…
PTPlot: a tool for exploring the gravitational wave power spectrum from first-order phase transitions
2022
PTPlot is a tool for exploring the gravitational wave power spectrum from first-order phase transitions, and evaluating the likelihood of detecting a signal with the LISA mission. The results plotted by this tool are based on the paper Detecting gravitational waves from cosmological phase transitions with LISA: an update, arXiv:1910.13125, which has been published in JCAP. Please cite both that paper, and this Zenodo deposit, if possible. The source for PTPlot is available at https://bitbucket.org/dweir/ptplot.