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Wojciech Rozmus - One of the best experts on this subject based on the ideXlab platform.

  • Nonequilibrium Electron Distribution functions and nonlinear thermal transport
    Physics of Plasmas, 2004
    Co-Authors: S. G. Bochkarev, V. Yu. Bychenkov, Wojciech Rozmus
    Abstract:

    Quasi-self-similar solutions to the stationary Electron kinetic equation in diffusive approximation have been found in an inhomogeneous plasma. Electron density and temperature corresponding to these solutions satisfy a steady state plasma profile that is defined by nTa=const (a>1). The derived Electron Distribution functions describe particle transport, in particular thermal conduction and ambiporal electric field for the arbitrary amplitude of temperature perturbation in the wide range of particle collisionality. The quasi-self-similar solutions display enhanced algebraic tails in the isotropic part and the reduced number of energetic Electrons in the anisotropic part of Electron Distribution functions. The quasi-self-similar theory of Electron kinetics is applied to laser plasma heating and heat transport into the overdense region. Calculations of the linear Landau damping rate, growth rate of the return current instability, and dynamical form factor are presented.

  • Nonequilibrium Electron Distribution functions and nonlinear thermal transport
    Physics of Plasmas, 2004
    Co-Authors: S. G. Bochkarev, V. Yu. Bychenkov, Wojciech Rozmus
    Abstract:

    Quasi-self-similar solutions to the stationary Electron kinetic equation in diffusive approximation have been found in an inhomogeneous plasma. Electron density and temperature corresponding to these solutions satisfy a steady state plasma profile that is defined by nTa=const (a>1). The derived Electron Distribution functions describe particle transport, in particular thermal conduction and ambiporal electric field for the arbitrary amplitude of temperature perturbation in the wide range of particle collisionality. The quasi-self-similar solutions display enhanced algebraic tails in the isotropic part and the reduced number of energetic Electrons in the anisotropic part of Electron Distribution functions. The quasi-self-similar theory of Electron kinetics is applied to laser plasma heating and heat transport into the overdense region. Calculations of the linear Landau damping rate, growth rate of the return current instability, and dynamical form factor are presented.

  • Nonthermal tails of the Electron Distribution functions with nonlocal transport
    ECLIM 2002: 27th European Conference on Laser Interaction with Matter, 2003
    Co-Authors: V. Yu. Bychenkov, O V Batishchev, Wojciech Rozmus, S. G. Bochkarev, J. J. Martinell, T. K. Soboleva
    Abstract:

    Quasi-self-similar solutions to the stationary Electron Fokker-Planck equation in diffusive approximation have been found in inhomogeneous plasma. These solutions describe reduction in the number of bulk Electrons and formation of the suprathermal tail. The characteristics of the stationary Electron Distributions have been treated in terms of the collisionality parameter, the ratio of the Electron stoping rage to the plasma gradient scale length. The dependencies of the Electron Distribution functions on density profile has been studied. Fokker-Plank simulations performed demonstrate good agreement with a theory.

  • heat transport and Electron Distribution function in laser produced plasmas with hot spots
    Physics of Plasmas, 2002
    Co-Authors: O V Batishchev, Richard D. Sydora, F Detering, Wojciech Rozmus, C E Capjack, Yu V Bychenkov, V N Novikov
    Abstract:

    Using Fokker–Planck and particle-in-cell simulations, the evolution of a single hot spot and multiple hot spot systems have been studied in laser produced plasmas. A practical formula for nonlocal heat flux has been derived as a generalized expression of a nonlocal linear approach [Bychenkov et al., Phys. Rev. Lett. 75, 4405 (1995)] and is tested in simulations. The Electron Distribution function is studied at different spatial locations with respect to a localized heating source. The Electron Distribution function displays several non-Maxwellian features which depend on the interplay between the effects of inverse bremsstrahlung heating and nonlocal transport. In particular, significant high-energy tails are found. They may have impact on the behavior of parametric instabilities in nonuniformly heated laser plasma.

  • Electron Distribution function in laser heated plasmas
    Physics of Plasmas, 2001
    Co-Authors: E Fourkal, Richard D. Sydora, Siegfried H. Glenzer, C Kirkby, Wojciech Rozmus, C E Capjack, Yu V Bychenkov, H A Baldis
    Abstract:

    A new Electron Distribution function has been found in laser heated homogeneous plasmas by an analytical solution to the kinetic equation and by particle simulations. The basic kinetic model describes inverse bremsstrahlung absorption and Electron–Electron collisions. The non-Maxwellian Distribution function is comprised of a super-Gaussian bulk of slow Electrons and a Maxwellian tail of energetic particles. The tails are heated due to Electron–Electron collisions and energy reDistribution between superthermal particles and light absorbing slow Electrons from the bulk of the Distribution function. A practical fit is proposed to the new Electron Distribution function. Changes to the linear Landau damping of Electron plasma waves are discussed. The first evidence for the existence of non-Maxwellian Distribution functions has been found in the interpretation, which includes the new Distribution function, of the Thomson scattering spectra in gold plasmas [Glenzer et al., Phys. Rev. Lett. 82, 97 (1999)].

Daigo Kobayashi - One of the best experts on this subject based on the ideXlab platform.

  • Phonon softening in sodium with a stepwise Electron Distribution
    Journal of Applied Physics, 2020
    Co-Authors: Shota Ono, Daigo Kobayashi
    Abstract:

    The absorption of light by a metal disturbs the Electron Distribution around the Fermi surface. Here, we calculate the phonon dispersion relations of free-Electron-like metal, bcc sodium, with a stepwise Electron Distribution function by using a model potential. The step can behave as a pseudo-Fermi surface, which produces singularities at specific wave numbers in the response function. The singularity gives rise to long-range oscillations in the interatomic potential and results in phonon softening along the Γ–N direction. The effect of the smearing in the step function is also discussed.

  • Pseudo-Fermi surface and phonon softening in sodium with a stepwise Electron Distribution
    arXiv: Materials Science, 2019
    Co-Authors: Shota Ono, Daigo Kobayashi
    Abstract:

    The absorption of light by a metal disturbs the Electron Distribution around the Fermi surface. Here, we calculate the phonon dispersion relations of free-Electron-like metal, bcc sodium, with a stepwise Electron Distribution function by using a model pseudo-potential method. The step can behave as a pseudo-Fermi surface, which produces the singularities at specific wavenumbers in the response function. The singularity gives rise to long-range oscillations in the interatomic potential and results in imaginary phonon frequencies around the N point.

O V Batishchev - One of the best experts on this subject based on the ideXlab platform.

  • Nonthermal tails of the Electron Distribution functions with nonlocal transport
    ECLIM 2002: 27th European Conference on Laser Interaction with Matter, 2003
    Co-Authors: V. Yu. Bychenkov, O V Batishchev, Wojciech Rozmus, S. G. Bochkarev, J. J. Martinell, T. K. Soboleva
    Abstract:

    Quasi-self-similar solutions to the stationary Electron Fokker-Planck equation in diffusive approximation have been found in inhomogeneous plasma. These solutions describe reduction in the number of bulk Electrons and formation of the suprathermal tail. The characteristics of the stationary Electron Distributions have been treated in terms of the collisionality parameter, the ratio of the Electron stoping rage to the plasma gradient scale length. The dependencies of the Electron Distribution functions on density profile has been studied. Fokker-Plank simulations performed demonstrate good agreement with a theory.

  • heat transport and Electron Distribution function in laser produced plasmas with hot spots
    Physics of Plasmas, 2002
    Co-Authors: O V Batishchev, Richard D. Sydora, F Detering, Wojciech Rozmus, C E Capjack, Yu V Bychenkov, V N Novikov
    Abstract:

    Using Fokker–Planck and particle-in-cell simulations, the evolution of a single hot spot and multiple hot spot systems have been studied in laser produced plasmas. A practical formula for nonlocal heat flux has been derived as a generalized expression of a nonlocal linear approach [Bychenkov et al., Phys. Rev. Lett. 75, 4405 (1995)] and is tested in simulations. The Electron Distribution function is studied at different spatial locations with respect to a localized heating source. The Electron Distribution function displays several non-Maxwellian features which depend on the interplay between the effects of inverse bremsstrahlung heating and nonlocal transport. In particular, significant high-energy tails are found. They may have impact on the behavior of parametric instabilities in nonuniformly heated laser plasma.

Shota Ono - One of the best experts on this subject based on the ideXlab platform.

  • Phonon softening in sodium with a stepwise Electron Distribution
    Journal of Applied Physics, 2020
    Co-Authors: Shota Ono, Daigo Kobayashi
    Abstract:

    The absorption of light by a metal disturbs the Electron Distribution around the Fermi surface. Here, we calculate the phonon dispersion relations of free-Electron-like metal, bcc sodium, with a stepwise Electron Distribution function by using a model potential. The step can behave as a pseudo-Fermi surface, which produces singularities at specific wave numbers in the response function. The singularity gives rise to long-range oscillations in the interatomic potential and results in phonon softening along the Γ–N direction. The effect of the smearing in the step function is also discussed.

  • Pseudo-Fermi surface and phonon softening in sodium with a stepwise Electron Distribution
    arXiv: Materials Science, 2019
    Co-Authors: Shota Ono, Daigo Kobayashi
    Abstract:

    The absorption of light by a metal disturbs the Electron Distribution around the Fermi surface. Here, we calculate the phonon dispersion relations of free-Electron-like metal, bcc sodium, with a stepwise Electron Distribution function by using a model pseudo-potential method. The step can behave as a pseudo-Fermi surface, which produces the singularities at specific wavenumbers in the response function. The singularity gives rise to long-range oscillations in the interatomic potential and results in imaginary phonon frequencies around the N point.

V N Novikov - One of the best experts on this subject based on the ideXlab platform.

  • heat transport and Electron Distribution function in laser produced plasmas with hot spots
    Physics of Plasmas, 2002
    Co-Authors: O V Batishchev, Richard D. Sydora, F Detering, Wojciech Rozmus, C E Capjack, Yu V Bychenkov, V N Novikov
    Abstract:

    Using Fokker–Planck and particle-in-cell simulations, the evolution of a single hot spot and multiple hot spot systems have been studied in laser produced plasmas. A practical formula for nonlocal heat flux has been derived as a generalized expression of a nonlocal linear approach [Bychenkov et al., Phys. Rev. Lett. 75, 4405 (1995)] and is tested in simulations. The Electron Distribution function is studied at different spatial locations with respect to a localized heating source. The Electron Distribution function displays several non-Maxwellian features which depend on the interplay between the effects of inverse bremsstrahlung heating and nonlocal transport. In particular, significant high-energy tails are found. They may have impact on the behavior of parametric instabilities in nonuniformly heated laser plasma.