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Title: Simulations of Electron Transport in Laser Hot Spots

Abstract

Simulations of electron transport are carried out by solving the Fokker-Planck equation in the diffusive approximation. The system of a single laser hot spot, with open boundary conditions, is systematically studied by performing a scan over a wide range of the two relevant parameters: (1) Ratio of the stopping length over the width of the hot spot. (2) Relative importance of the heating through inverse Bremsstrahlung compared to the thermalization through self-collisions. As for uniform illumination [J.P. Matte et al., Plasma Phys. Controlled Fusion 30 (1988) 1665], the bulk of the velocity distribution functions (VDFs) present a super-Gaussian dependence. However, as a result of spatial transport, the tails are observed to be well represented by a Maxwellian. A similar dependence of the distributions is also found for multiple hot spot systems. For its relevance with respect to stimulated Raman scattering, the linear Landau damping of the electron plasma wave is estimated for such VD Fs. Finally, the nonlinear Fokker-Planck simulations of the single laser hot spot system are also compared to the results obtained with the linear non-local hydrodynamic approach [A.V. Brantov et al., Phys. Plasmas 5 (1998) 2742], thus providing a quantitative limit to the latter method: The hydrodynamicmore » approach presents more than 10% inaccuracy in the presence of temperature variations of the order delta T/T greater than or equal to 1%, and similar levels of deformation of the Gaussian shape of the Maxwellian background.« less

Authors:
;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab., NJ (US)
Sponsoring Org.:
USDOE Office of Science (US)
OSTI Identifier:
787905
Report Number(s):
PPPL-3599
TRN: US0110755
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 30 Aug 2001
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BOUNDARY CONDITIONS; DISTRIBUTION FUNCTIONS; ELECTRON PLASMA WAVES; FOKKER-PLANCK EQUATION; HOT SPOTS; LANDAU DAMPING; LASERS; COMPUTERIZED SIMULATION; ELECTRON TRANSFER

Citation Formats

S. Brunner, and E. Valeo. Simulations of Electron Transport in Laser Hot Spots. United States: N. p., 2001. Web. doi:10.2172/787905.
S. Brunner, & E. Valeo. Simulations of Electron Transport in Laser Hot Spots. United States. doi:10.2172/787905.
S. Brunner, and E. Valeo. Thu . "Simulations of Electron Transport in Laser Hot Spots". United States. doi:10.2172/787905. https://www.osti.gov/servlets/purl/787905.
@article{osti_787905,
title = {Simulations of Electron Transport in Laser Hot Spots},
author = {S. Brunner and E. Valeo},
abstractNote = {Simulations of electron transport are carried out by solving the Fokker-Planck equation in the diffusive approximation. The system of a single laser hot spot, with open boundary conditions, is systematically studied by performing a scan over a wide range of the two relevant parameters: (1) Ratio of the stopping length over the width of the hot spot. (2) Relative importance of the heating through inverse Bremsstrahlung compared to the thermalization through self-collisions. As for uniform illumination [J.P. Matte et al., Plasma Phys. Controlled Fusion 30 (1988) 1665], the bulk of the velocity distribution functions (VDFs) present a super-Gaussian dependence. However, as a result of spatial transport, the tails are observed to be well represented by a Maxwellian. A similar dependence of the distributions is also found for multiple hot spot systems. For its relevance with respect to stimulated Raman scattering, the linear Landau damping of the electron plasma wave is estimated for such VD Fs. Finally, the nonlinear Fokker-Planck simulations of the single laser hot spot system are also compared to the results obtained with the linear non-local hydrodynamic approach [A.V. Brantov et al., Phys. Plasmas 5 (1998) 2742], thus providing a quantitative limit to the latter method: The hydrodynamic approach presents more than 10% inaccuracy in the presence of temperature variations of the order delta T/T greater than or equal to 1%, and similar levels of deformation of the Gaussian shape of the Maxwellian background.},
doi = {10.2172/787905},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Aug 30 00:00:00 EDT 2001},
month = {Thu Aug 30 00:00:00 EDT 2001}
}

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