The Experts below are selected from a list of 51576 Experts worldwide ranked by ideXlab platform

A. Ghysels - One of the best experts on this subject based on the ideXlab platform.

Vincent Rossetto - One of the best experts on this subject based on the ideXlab platform.

  • Measuring the scattering Mean Free Path of Rayleigh waves on a volcano from spatial phase decoherence
    Geophysical Journal International, 2014
    Co-Authors: Anne Obermann, Éric Larose, Ludovic Margerin, Vincent Rossetto
    Abstract:

    We analyse the statistics of phase fluctuations of seismic signals obtained from a temporary small aperture array deployed on a volcano in the French Auvergne. We demonstrate that the phase field satisfies Circular Gaussian statistics. We then determine the scattering Mean Free Path of Rayleigh waves from the spatial phase decoherence. This phenomenon, observed for diffuse wavefields, is found to yield a good approximation of the scattering Mean Free Path. Contrary to the amplitude, spatial phase decoherence is Free from absorption effects and provides direct access to the scattering Mean Free Path.

H Q He - One of the best experts on this subject based on the ideXlab platform.

  • a simple analytical method to determine solar energetic particles Mean Free Path
    The Astrophysical Journal, 2011
    Co-Authors: H Q He
    Abstract:

    To obtain the Mean Free Path of solar energetic particles (SEPs) for a solar event, one usually has to fit time profiles of both flux and anisotropy from spacecraft observations to numerical simulations of SEPs' transport processes. This method can be called a simulation method. But a reasonably good fitting needs a lot of simulations, which demand a large amount of calculation resources. Sometimes, it is necessary to find an easy way to obtain the Mean Free Path of SEPs quickly, for example, in space weather practice. Recently, Shalchi et al. provided an approximate analytical formula of SEPs' anisotropy time profile as a function of particles' Mean Free Path for impulsive events. In this paper, we determine SEPs' Mean Free Path by fitting the anisotropy time profiles from Shalchi et al.'s analytical formula to spacecraft observations. This new method can be called an analytical method. In addition, we obtain SEPs' Mean Free Path with the traditional simulation methods. Finally, we compare the Mean Free Path obtained with the simulation method to that of the analytical method to show that the analytical method, with some minor modifications, can give us a good, quick approximation of SEPs' Mean Free Path for impulsive events.

Arnau Rios - One of the best experts on this subject based on the ideXlab platform.

  • Nucleon Mean-Free Path in the medium
    EPJ Web of Conferences, 2014
    Co-Authors: V. Somà, Arnau Rios
    Abstract:

    A microscopic determination of the Mean-Free Path of a nucleon in symmetric nuclear matter is presented. Calculations are based on self-consistent Green's functions theory within the ladder approximation and use di erent realistic nucleon-nucleon po- tentials supplemented by semi-phenomenological three-body forces. Temperature and density dependence are discussed. At zero temperature and nuclear saturation density we find that, for energies above 50 MeV, a nucleon has a Mean-Free Path of 4 to 5 fermi.

  • Self-consistent Green's functions calculation of the nucleon Mean-Free Path
    Journal of Physics: Conference Series, 2013
    Co-Authors: Arnau Rios, V. Somà
    Abstract:

    Transport coefficients provide a unique insight into the near-equilibrium behavior of quantum many-body systems. The Mean-Free Path, λ, of a particle within a dense medium is a basic transport coefficient, at the basis of several theoretical concepts and closely related to experimentally measured quantities. Green's functions techniques are particularly well suited to study such transport properties, since they are naturally formulated in the time domain. We present a calculation of the Mean-Free Path of a nucleon in symmetric nuclear matter using self-consistent ladder self-energies extended to the complex energy plane. Our results indicate that, for energies above 50 MeV at densities close to saturation, a nucleon has a Mean-Free Path of 4 to 5 femtometers.

  • self consistent green s function calculation of the nucleon Mean Free Path
    Physical Review Letters, 2012
    Co-Authors: Arnau Rios
    Abstract:

    The extension of Green's functions techniques to the complex energy plane provides access to fully dressed quasiparticle properties from a microscopic perspective. Using self-consistent ladder self-energies, we find both spectra and lifetimes of such quasiparticles in nuclear matter. With a consistent choice of the group velocity, the nucleon Mean-Free Path can be computed. Our results indicate that, for energies above 50 MeV at densities close to saturation, a nucleon has a Mean-Free Path of 4 to 5 fm.

Ruth Signorell - One of the best experts on this subject based on the ideXlab platform.

  • electron Mean Free Path from angle dependent photoelectron spectroscopy of aerosol particles
    Journal of Chemical Physics, 2015
    Co-Authors: Maximilian Goldmann, J Miguelsanchez, Adam H C West, Bruce L Yoder, Ruth Signorell
    Abstract:

    We propose angle-resolved photoelectron spectroscopy of aerosol particles as an alternative way to determine the electron Mean Free Path of low energy electrons in solid and liquid materials. The Mean Free Path is obtained from fits of simulated photoemission images to experimental ones over a broad range of different aerosol particle sizes. The principal advantage of the aerosol approach is twofold. First, aerosol photoemission studies can be performed for many different materials, including liquids. Second, the size-dependent anisotropy of the photoelectrons can be exploited in addition to size-dependent changes in their kinetic energy. These finite size effects depend in different ways on the Mean Free Path and thus provide more information on the Mean Free Path than corresponding liquid jet, thin film, or bulk data. The present contribution is a proof of principle employing a simple model for the photoemission of electrons and preliminary experimental data for potassium chloride aerosol particles.