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Richard M. Thorne - One of the best experts on this subject based on the ideXlab platform.

  • A new Diffusion Matrix for whistler mode chorus waves
    Journal of Geophysical Research, 2013
    Co-Authors: Richard B. Horne, Tobias Kersten, Sarah A. Glauert, Nigel P. Meredith, Daniel Boscher, A. Sicard-piet, Richard M. Thorne
    Abstract:

    [1] Global models of the Van Allen radiation belts usually include resonant wave-particle interactions as a Diffusion process, but there is a large uncertainty over the Diffusion rates. Here we present a new Diffusion Matrix for whistler mode chorus waves that can be used in such models. Data from seven satellites are used to construct 3536 power spectra for upper and lower band chorus for 1.5≤L∗≤10 MLT, magnetic latitude 0°≤|λm|≤60° and five levels of Kp. Five density models are also constructed from the data. Gaussian functions are fitted to the spectra and capture typically 90% of the wave power. The frequency maxima of the power spectra vary with L∗ and are typically lower than that used previously. Lower band chorus Diffusion increases with geomagnetic activity and is largest between 21:00 and 12:00 MLT. Energy Diffusion extends to a few megaelectron volts at large pitch angles >60° and at high energies exceeds pitch angle Diffusion at the loss cone. Most electron Diffusion occurs close to the geomagnetic equator (

  • a new Diffusion Matrix for whistler mode chorus waves
    Journal of Geophysical Research, 2013
    Co-Authors: Richard B. Horne, Tobias Kersten, Sarah A. Glauert, Nigel P. Meredith, Daniel Boscher, A Sicardpiet, Richard M. Thorne
    Abstract:

    [1] Global models of the Van Allen radiation belts usually include resonant wave-particle interactions as a Diffusion process, but there is a large uncertainty over the Diffusion rates. Here we present a new Diffusion Matrix for whistler mode chorus waves that can be used in such models. Data from seven satellites are used to construct 3536 power spectra for upper and lower band chorus for 1.5≤L∗≤10 MLT, magnetic latitude 0°≤|λm|≤60° and five levels of Kp. Five density models are also constructed from the data. Gaussian functions are fitted to the spectra and capture typically 90% of the wave power. The frequency maxima of the power spectra vary with L∗ and are typically lower than that used previously. Lower band chorus Diffusion increases with geomagnetic activity and is largest between 21:00 and 12:00 MLT. Energy Diffusion extends to a few megaelectron volts at large pitch angles >60° and at high energies exceeds pitch angle Diffusion at the loss cone. Most electron Diffusion occurs close to the geomagnetic equator (<12°). Pitch angle Diffusion rates for lower band chorus increase with L∗ and are significant at L∗=8 even for low levels of geomagnetic activity, while upper band chorus is restricted to mainly L∗<6. The combined drift and bounce averaged Diffusion rates for upper and lower band chorus extend from a few kiloelectron volts near the loss cone up to several megaelectron volts at large pitch angles indicating loss at low energies and net acceleration at high energies.

Richard B. Horne - One of the best experts on this subject based on the ideXlab platform.

  • A new Diffusion Matrix for whistler mode chorus waves
    Journal of Geophysical Research, 2013
    Co-Authors: Richard B. Horne, Tobias Kersten, Sarah A. Glauert, Nigel P. Meredith, Daniel Boscher, A. Sicard-piet, Richard M. Thorne
    Abstract:

    [1] Global models of the Van Allen radiation belts usually include resonant wave-particle interactions as a Diffusion process, but there is a large uncertainty over the Diffusion rates. Here we present a new Diffusion Matrix for whistler mode chorus waves that can be used in such models. Data from seven satellites are used to construct 3536 power spectra for upper and lower band chorus for 1.5≤L∗≤10 MLT, magnetic latitude 0°≤|λm|≤60° and five levels of Kp. Five density models are also constructed from the data. Gaussian functions are fitted to the spectra and capture typically 90% of the wave power. The frequency maxima of the power spectra vary with L∗ and are typically lower than that used previously. Lower band chorus Diffusion increases with geomagnetic activity and is largest between 21:00 and 12:00 MLT. Energy Diffusion extends to a few megaelectron volts at large pitch angles >60° and at high energies exceeds pitch angle Diffusion at the loss cone. Most electron Diffusion occurs close to the geomagnetic equator (

  • a new Diffusion Matrix for whistler mode chorus waves
    Journal of Geophysical Research, 2013
    Co-Authors: Richard B. Horne, Tobias Kersten, Sarah A. Glauert, Nigel P. Meredith, Daniel Boscher, A Sicardpiet, Richard M. Thorne
    Abstract:

    [1] Global models of the Van Allen radiation belts usually include resonant wave-particle interactions as a Diffusion process, but there is a large uncertainty over the Diffusion rates. Here we present a new Diffusion Matrix for whistler mode chorus waves that can be used in such models. Data from seven satellites are used to construct 3536 power spectra for upper and lower band chorus for 1.5≤L∗≤10 MLT, magnetic latitude 0°≤|λm|≤60° and five levels of Kp. Five density models are also constructed from the data. Gaussian functions are fitted to the spectra and capture typically 90% of the wave power. The frequency maxima of the power spectra vary with L∗ and are typically lower than that used previously. Lower band chorus Diffusion increases with geomagnetic activity and is largest between 21:00 and 12:00 MLT. Energy Diffusion extends to a few megaelectron volts at large pitch angles >60° and at high energies exceeds pitch angle Diffusion at the loss cone. Most electron Diffusion occurs close to the geomagnetic equator (<12°). Pitch angle Diffusion rates for lower band chorus increase with L∗ and are significant at L∗=8 even for low levels of geomagnetic activity, while upper band chorus is restricted to mainly L∗<6. The combined drift and bounce averaged Diffusion rates for upper and lower band chorus extend from a few kiloelectron volts near the loss cone up to several megaelectron volts at large pitch angles indicating loss at low energies and net acceleration at high energies.

Mohamed Ichchou - One of the best experts on this subject based on the ideXlab platform.

  • Multimodal wave propagation in smart composite structures with shunted piezoelectric patches
    Journal of Intelligent Material Systems and Structures, 2013
    Co-Authors: Tianli Huang, Mohamed Ichchou, Olivier Bareille, Manuel Collet, Morvan Ouisse
    Abstract:

    Wave propagation in composite structures with shunted piezoelectric patches is investigated in this study. The wave finite element approach is first developed as a prediction tool for wave propagation characteristics such as dispersion curves in composite structures, and subsequently extended to consider shunted piezoelectric elements through the Diffusion Matrix model. A three-layered composite beam equipped with a pair of resistor–inductor shunted piezoelectric patches is modeled and analyzed carefully with these numerical techniques. Reflection and transmission coefficients of propagating waves in this smart composite structure are calculated, and the performance of shunted piezoelectric patches on the control of wave propagation is investigated numerically with the Diffusion Matrix model. Another finite element formulation, named modified wave finite element method, which is dedicated to the analysis of wave propagation in multilayered composite structures, is proposed and developed for considering pi...

  • Review: Diffusion Matrix through stochastic wave finite element method
    Finite Elements in Analysis and Design, 2013
    Co-Authors: Faker Bouchoucha, Mohamed Ichchou, Mohamed Haddar
    Abstract:

    Diffusion Matrix for uncertain media through stochastic wave finite element method (SWFEM) is presented in this paper. The presented stochastic Diffusion relationship allows evaluating the statistics of reflection and transmission coefficients under structural uncertainty. The uncertain material properties are modeled as a set of random fields. The structure is presented considering two waveguides connected through a stochastic coupling element, simulated as the defect (crack). In this work, a SWFEM is employed in order to analyze the stochastic wave/damage interaction and the numerical accuracy and the computational efficiency of the method are demonstrated by comparison with analytical results.

  • Multimodal wave propagation in smart composite structures with shunted piezoelectric patches
    Journal of Intelligent Material Systems and Structures, 2013
    Co-Authors: Tianli Huang, Mohamed Ichchou, Olivier Bareille, Manuel Collet, Morvan Ouisse
    Abstract:

    Wave propagation in composite structures with shunted piezoelectric patches is investigated in this study. The wave finite element approach is first developed as a prediction tool for wave propagation characteristics such as dispersion curves in composite structures, and subsequently extended to consider shunted piezoelectric elements through the Diffusion Matrix model. A three-layered composite beam equipped with a pair of resistor-inductor shunted piezoelectric patches is modeled and analyzed carefully with these numerical techniques. Reflection and transmission coefficients of propagating waves in this smart composite structure are calculated, and the performance of shunted piezoelectric patches on the control of wave propagation is investigated numerically with the Diffusion Matrix model. Another finite element formulation, named modified wave finite element method, which is dedicated to the analysis of wave propagation in multilayered composite structures, is proposed and developed for considering piezoelectric elements in the structures. It is a dynamic substructuring technique that allows the dynamics of a typical layer cross section to be projected on a reduced local wave mode basis with appropriate dimensions. Results issued from this method are compared to those issued from the classical wave finite element and Diffusion Matrix model formulations to demonstrate the pertinence of the modelings.

  • Multi-modal wave propagation in smart composite structures with shunted piezoelectric patches
    2012
    Co-Authors: Tianli Huang, Mohamed Ichchou, Manuel Collet, Flaviano Tateo, Morvan Ouisse
    Abstract:

    Wave propagation in composite structures with shunted piezoelectric patches is investigated in this study. The wave finite element approach is first developed as a prediction tool for wave propagation characteristics such as dispersion curves in composite structures, and subsequently extended to consider shunted piezoelectric elements through the Diffusion Matrix model. A three-layered composite beam equipped with a pair of resistor–inductor shunted piezoelectric patches is modeled and analyzed carefully with these numerical techniques. Reflection and transmission coefficients of propagating waves in this smart composite structure are calculated, and the performance of shunted piezoelectric patches on the control of wave propagation is investigated numerically with the Diffusion Matrix model. Another finite element formulation, named modified wave finite element method, which is dedicated to the analysis of wave propagation in multilayered composite structures, is proposed and developed for considering piezoelectric elements in the structures. It is a dynamic substructuring technique that allows the dynamics of a typical layer cross section to be projected on a reduced local wave mode basis with appropriate dimensions. Results issued from this method are compared to those issued from the classical wave finite element and Diffusion Matrix model formulations to demonstrate the pertinence of the modelings.

  • Damage Detection in Cylindrical Pipe through Diffusion Matrix in Wave Finite Element Method
    Advances in Structural Engineering, 2012
    Co-Authors: Faker Bouchoucha, Mohamed Ichchou, M. Akrout, Tahar Fakhfakh, Mohamed Haddar
    Abstract:

    This paper addresses the question of damage detection of cylindrical structures using finite element and periodic structure theory. The structure is modeled considering two waveguides connected through a coupling element, simulated as the defect. Wave characteristics in the waveguides are evaluated using a Wave Finite Element method (W.F.E.M) based on the analysis of the anomalies which affect the elastic wave travelling in the structure. Reflection and transmission coefficients of the wave modes which are incident to the coupling element are provided by a Diffusion Matrix. Then forced response of the pipe with and without transversal defect is predicted using wave decomposition. Numerical examples are given. These concern an isotropic pipe, for which dispersion curves are provided and Diffusion coefficients in presence of a transversal and a longitudinal defect are predicted.

Morvan Ouisse - One of the best experts on this subject based on the ideXlab platform.

  • Multimodal wave propagation in smart composite structures with shunted piezoelectric patches
    Journal of Intelligent Material Systems and Structures, 2013
    Co-Authors: Tianli Huang, Mohamed Ichchou, Olivier Bareille, Manuel Collet, Morvan Ouisse
    Abstract:

    Wave propagation in composite structures with shunted piezoelectric patches is investigated in this study. The wave finite element approach is first developed as a prediction tool for wave propagation characteristics such as dispersion curves in composite structures, and subsequently extended to consider shunted piezoelectric elements through the Diffusion Matrix model. A three-layered composite beam equipped with a pair of resistor–inductor shunted piezoelectric patches is modeled and analyzed carefully with these numerical techniques. Reflection and transmission coefficients of propagating waves in this smart composite structure are calculated, and the performance of shunted piezoelectric patches on the control of wave propagation is investigated numerically with the Diffusion Matrix model. Another finite element formulation, named modified wave finite element method, which is dedicated to the analysis of wave propagation in multilayered composite structures, is proposed and developed for considering pi...

  • Multimodal wave propagation in smart composite structures with shunted piezoelectric patches
    Journal of Intelligent Material Systems and Structures, 2013
    Co-Authors: Tianli Huang, Mohamed Ichchou, Olivier Bareille, Manuel Collet, Morvan Ouisse
    Abstract:

    Wave propagation in composite structures with shunted piezoelectric patches is investigated in this study. The wave finite element approach is first developed as a prediction tool for wave propagation characteristics such as dispersion curves in composite structures, and subsequently extended to consider shunted piezoelectric elements through the Diffusion Matrix model. A three-layered composite beam equipped with a pair of resistor-inductor shunted piezoelectric patches is modeled and analyzed carefully with these numerical techniques. Reflection and transmission coefficients of propagating waves in this smart composite structure are calculated, and the performance of shunted piezoelectric patches on the control of wave propagation is investigated numerically with the Diffusion Matrix model. Another finite element formulation, named modified wave finite element method, which is dedicated to the analysis of wave propagation in multilayered composite structures, is proposed and developed for considering piezoelectric elements in the structures. It is a dynamic substructuring technique that allows the dynamics of a typical layer cross section to be projected on a reduced local wave mode basis with appropriate dimensions. Results issued from this method are compared to those issued from the classical wave finite element and Diffusion Matrix model formulations to demonstrate the pertinence of the modelings.

  • Multi-modal wave propagation in smart composite structures with shunted piezoelectric patches
    2012
    Co-Authors: Tianli Huang, Mohamed Ichchou, Manuel Collet, Flaviano Tateo, Morvan Ouisse
    Abstract:

    Wave propagation in composite structures with shunted piezoelectric patches is investigated in this study. The wave finite element approach is first developed as a prediction tool for wave propagation characteristics such as dispersion curves in composite structures, and subsequently extended to consider shunted piezoelectric elements through the Diffusion Matrix model. A three-layered composite beam equipped with a pair of resistor–inductor shunted piezoelectric patches is modeled and analyzed carefully with these numerical techniques. Reflection and transmission coefficients of propagating waves in this smart composite structure are calculated, and the performance of shunted piezoelectric patches on the control of wave propagation is investigated numerically with the Diffusion Matrix model. Another finite element formulation, named modified wave finite element method, which is dedicated to the analysis of wave propagation in multilayered composite structures, is proposed and developed for considering piezoelectric elements in the structures. It is a dynamic substructuring technique that allows the dynamics of a typical layer cross section to be projected on a reduced local wave mode basis with appropriate dimensions. Results issued from this method are compared to those issued from the classical wave finite element and Diffusion Matrix model formulations to demonstrate the pertinence of the modelings.

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

  • A new Diffusion Matrix for whistler mode chorus waves
    Journal of Geophysical Research, 2013
    Co-Authors: Richard B. Horne, Tobias Kersten, Sarah A. Glauert, Nigel P. Meredith, Daniel Boscher, A. Sicard-piet, Richard M. Thorne
    Abstract:

    [1] Global models of the Van Allen radiation belts usually include resonant wave-particle interactions as a Diffusion process, but there is a large uncertainty over the Diffusion rates. Here we present a new Diffusion Matrix for whistler mode chorus waves that can be used in such models. Data from seven satellites are used to construct 3536 power spectra for upper and lower band chorus for 1.5≤L∗≤10 MLT, magnetic latitude 0°≤|λm|≤60° and five levels of Kp. Five density models are also constructed from the data. Gaussian functions are fitted to the spectra and capture typically 90% of the wave power. The frequency maxima of the power spectra vary with L∗ and are typically lower than that used previously. Lower band chorus Diffusion increases with geomagnetic activity and is largest between 21:00 and 12:00 MLT. Energy Diffusion extends to a few megaelectron volts at large pitch angles >60° and at high energies exceeds pitch angle Diffusion at the loss cone. Most electron Diffusion occurs close to the geomagnetic equator (

  • a new Diffusion Matrix for whistler mode chorus waves
    Journal of Geophysical Research, 2013
    Co-Authors: Richard B. Horne, Tobias Kersten, Sarah A. Glauert, Nigel P. Meredith, Daniel Boscher, A Sicardpiet, Richard M. Thorne
    Abstract:

    [1] Global models of the Van Allen radiation belts usually include resonant wave-particle interactions as a Diffusion process, but there is a large uncertainty over the Diffusion rates. Here we present a new Diffusion Matrix for whistler mode chorus waves that can be used in such models. Data from seven satellites are used to construct 3536 power spectra for upper and lower band chorus for 1.5≤L∗≤10 MLT, magnetic latitude 0°≤|λm|≤60° and five levels of Kp. Five density models are also constructed from the data. Gaussian functions are fitted to the spectra and capture typically 90% of the wave power. The frequency maxima of the power spectra vary with L∗ and are typically lower than that used previously. Lower band chorus Diffusion increases with geomagnetic activity and is largest between 21:00 and 12:00 MLT. Energy Diffusion extends to a few megaelectron volts at large pitch angles >60° and at high energies exceeds pitch angle Diffusion at the loss cone. Most electron Diffusion occurs close to the geomagnetic equator (<12°). Pitch angle Diffusion rates for lower band chorus increase with L∗ and are significant at L∗=8 even for low levels of geomagnetic activity, while upper band chorus is restricted to mainly L∗<6. The combined drift and bounce averaged Diffusion rates for upper and lower band chorus extend from a few kiloelectron volts near the loss cone up to several megaelectron volts at large pitch angles indicating loss at low energies and net acceleration at high energies.