Search results for "Computation"
showing 10 items of 7362 documents
Results of a self-triggered prototype system for radio-detection of extensive air showers at the Pierre Auger Observatory
2012
We describe the experimental setup and the results of RAuger, a small radio-antenna array, consisting of three fully autonomous and self-triggered radio-detection stations, installed close to the center of the Surface Detector (SD) of the Pierre Auger Observatory in Argentina. The setup has been designed for the detection of the electric field strength of air showers initiated by ultra-high energy cosmic rays, without using an auxiliary trigger from another detection system. Installed in December 2006, RAuger was terminated in May 2010 after 65 registered coincidences with the SD. The sky map in local angular coordinates (i.e., zenith and azimuth angles) of these events reveals a strong azi…
Plasma diagnostic tools for ECR ion sources : What can we learn from these experiments for the next generation sources
2019
International audience; The order-of-magnitude performance leaps of ECR ion sources over the past decades result from improvements to the magnetic plasma confinement, increases in the microwave heating frequency, and techniques to stabilize the plasma at high densities. Parallel to the technical development of the ion sources themselves, significant effort has been directed into the development of their plasma diagnostic tools. We review the recent results of Electron Cyclotron Resonance Ion Source (ECRIS) plasma diagnostics highlighting a number of selected examples of plasma density, electron energy distribution, and ion confinement time measurements, obtained mostly with the second-gener…
Multi-resolution error analysis of predicted absorption coefficients. Method and computer implementation. Application to the IR spectrum of methane a…
2009
A general method for the estimation of the confidence interval of molecular absorption coefficients is presented. It combines statistical numerical experiments with analytical calculations. The method uses line parameter predictions (position and intensity) with known estimated uncertainties. The propagation of errors from line parameters to absorption coefficients or cross-sections are analyzed in detail as a function of the resolution. This work is especially intended to provide expert information for applications requiring theoretical predictions for which the present state of the art of line by line high-resolution modeling is not accurate enough to meet the experimental precision. As a…
The STDS Dijon system : Present status and prospects.
2009
The Dijon spectroscopy group has developed powerful techniques based on group theory and tensorial formalism in order to analyze and simulate absorption and Raman spectra of molecules with various symmetries. Software packages and databases implementing these tools have been created [1]. Compared to the widely used spectroscopic databases (HITRAN, GEISA), these packages, with their XTDS common interface [2], are primarily devoted to the calculation of line parameters and spectra from a database of model parameters. Future developments include improved fitting algorithms, inclusion of C3v symmetric tops, rovibronic couplings, uncertainty estimates. Moreover, calculated line lists will be acc…
Multi-Resolution error analysis of predicted absorption coefficients. Method and computer implementation. Application to the infrared spectrum of met…
2009
A general method for the estimation of the confidence interval of molecular absorption coefficients is presented. It combines statistical numerical experiments with analytical calculations. The method uses line parameter predictions (position and intensity) with known estimated uncertainties. The propagation of errors from line parameters to absorption coefficients or cross-sections are analyzed in detail as a function of the resolution. This work is especially intended to provide expert information for applications requiring theoretical predictions for which the present state of the art of line by line high-resolution modeling is not accurate enough to meet the experimental precision. As a…
Shallow water rogue waves in nonlinear optical fibers
2013
The dynamics of extreme waves, often known as freak or rogue waves (RW), is presently a subject of intensive research. In oceanography, RW are mostly known as a sudden deep-water event which is responsible for ship wreakages and can be modeled by the 1D Nonlinear Schrodinger Equation (NLSE). In this framework, an ideal testbed is provided by optical pulse propagation in nonlinear optical fibers: extreme solitary wave emissions during supercontinuum generation or the first experimental observation of the Peregrine solitons have indeed been carried out exploiting the modulation instability occuring in fibers with anomalous dispersion.
Peregrine soliton in optical fiber-based systems
2011
International audience; We report the first observation in optics of the Peregrine soliton, a novel class of nonlinear localized structure. Two experimental configurations are explored and the impact of non-ideal initial conditions is discussed.
Methane line parameters in HITRAN
2003
Abstract Two editions of the methane line parameters (line positions, intensities and broadening coefficients) available from HITRAN in 2000 and 2001 are described. In both versions, the spectral interval covered was the same (from 0.01 to 6184.5 cm −1 ), but the database increased from 48,033 transitions in 2000 to 211,465 lines in 2001 because weaker transitions of 12 CH 4 and new bands of 13 CH 4 and CH3D were included. The newer list became available in 2001 in the “Update” section of HITRAN. The sources of information are described, and the prospects for future improvements are discussed.
Statistical analysis of pulse propagation driven by polarization-mode dispersion
2002
International audience; The linear propagation of pulses driven by random polarization-mode dispersion is considered. Analytical expressions are derived for the probability-density functions of the pulse width, timing displacement, and degree of polarization. The study is performed in Stokes space, and frequency correlation between modes is shown to play an important role in it.
Temporal coherence in mirrorless optical parametric oscillators
2012
International audience; One of the unique features of mirrorless optical parametric oscillators based on counterpropagating three-wave interactions is the narrow spectral width of the wave generated in the backward direction. In this work, we in- vestigate experimentally and numerically the influence that a strong phase modulation in the pump has on the spectral bandwidths of the parametric waves and on the efficiency of the nonlinear interaction. The effects of group-velocity mismatch and group-velocity dispersion are elucidated. In particular, it is shown that the substan- tial increase in temporal coherence of the backward-generated wave can be obtained even for pumping with a temporally…