Parameterizing hot electron energy distributions for tabular emissivities and opacities

doi:10.1016/j.hedp.2019.100730

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Title: Parameterizing hot electron energy distributions for tabular emissivities and opacities

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Abstract

Cold Kα and Kβ emission spectroscopy is a powerful diagnostic for plasma conditions and distributions of energetic electrons produced in short pulse laser experiments. SPECT3D post-processes hydrodynamics code output and simulates high-resolution spectra and images for plasmas containing arbitrary distributions of hot electrons, however these calculations can become prohibitively expensive for plasmas requiring complex atomic data and detailed computational grids. To significantly increase calculation speed, it is desirable to use pre-configured opacity tables that include information about hot electrons, rather than calculating emissivity and opacity for every grid point by solving collisional-radiative atomic kinetic rate equations. However, to tabulate such opacities, a general parameter-based description of hot electron energy distributions must be found. To be practical, hot electrons should be represented with an analytic function of just a few parameters which, in addition to temperature and density, can be used to define parameter space for opacity tables. In this paper, we present a method that allows for describing a set of arbitrary binned hot electron distributions with a simple analytic function, with only a modest impact on the accuracy of the simulations. Increased calculation speeds of 50–100x are demonstrated. In conclusion, we also discuss details of opacity calculations and presentmore »« less

Authors:

Walton, T. ^[1]; Sebald, J. L. ^[1]; Golovkin, I. E. ^[1]; MacFarlane, J. J. ^[1]; Golovkina, V. N. ^[1]; Solodov, A. A. ^[2]; Nilson, P. M. ^[2]; Epstein, R. ^[2]

Prism Computational Sciences, Madison, WI (United States)
Univ. of Rochester, NY (United States). Lab. for Laser Energetics

Publication Date:: 2019-11-02

Research Org.:: Prism Computational Sciences, Madison, WI (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)

OSTI Identifier:: 1593393

Alternate Identifier(s):: OSTI ID: 1574530

Grant/Contract Number:: SC0018105

Resource Type:: Accepted Manuscript

Journal Name:: High Energy Density Physics

Additional Journal Information:: Journal Volume: 35; Journal Issue: C; Journal ID: ISSN 1574-1818

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 74 ATOMIC AND MOLECULAR PHYSICS; short pulse lasers; non-maxwellian electrons; warm dense matter; plasma spectroscopy; synthetic diagnostic

Citation Formats


                    Walton, T., Sebald, J. L., Golovkin, I. E., MacFarlane, J. J., Golovkina, V. N., Solodov, A. A., Nilson, P. M., and Epstein, R. Parameterizing hot electron energy distributions for tabular emissivities and opacities.  United States: N. p., 2019. 
        Web.  doi:10.1016/j.hedp.2019.100730.

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                    Walton, T., Sebald, J. L., Golovkin, I. E., MacFarlane, J. J., Golovkina, V. N., Solodov, A. A., Nilson, P. M., & Epstein, R. Parameterizing hot electron energy distributions for tabular emissivities and opacities.  United States.  doi:10.1016/j.hedp.2019.100730.

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                    Walton, T., Sebald, J. L., Golovkin, I. E., MacFarlane, J. J., Golovkina, V. N., Solodov, A. A., Nilson, P. M., and Epstein, R. Sat .  
        "Parameterizing hot electron energy distributions for tabular emissivities and opacities".  United States.  doi:10.1016/j.hedp.2019.100730.

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@article{osti_1593393,

  title        = {Parameterizing hot electron energy distributions for tabular emissivities and opacities},

  author       = {Walton, T. and Sebald, J. L. and Golovkin, I. E. and MacFarlane, J. J. and Golovkina, V. N. and Solodov, A. A. and Nilson, P. M. and Epstein, R.},

  abstractNote = {Cold Kα and Kβ emission spectroscopy is a powerful diagnostic for plasma conditions and distributions of energetic electrons produced in short pulse laser experiments. SPECT3D post-processes hydrodynamics code output and simulates high-resolution spectra and images for plasmas containing arbitrary distributions of hot electrons, however these calculations can become prohibitively expensive for plasmas requiring complex atomic data and detailed computational grids. To significantly increase calculation speed, it is desirable to use pre-configured opacity tables that include information about hot electrons, rather than calculating emissivity and opacity for every grid point by solving collisional-radiative atomic kinetic rate equations. However, to tabulate such opacities, a general parameter-based description of hot electron energy distributions must be found. To be practical, hot electrons should be represented with an analytic function of just a few parameters which, in addition to temperature and density, can be used to define parameter space for opacity tables. In this paper, we present a method that allows for describing a set of arbitrary binned hot electron distributions with a simple analytic function, with only a modest impact on the accuracy of the simulations. Increased calculation speeds of 50–100x are demonstrated. In conclusion, we also discuss details of opacity calculations and present synthetic spectroscopy data based on post-processing of detailed particle-in-cell simulations relevant to the ongoing experimental campaign at the Omega EP laser facility.},

  doi          = {10.1016/j.hedp.2019.100730},

  journal      = {High Energy Density Physics},

  number       = C,

  volume       = 35,

  place        = {United States},

  year         = {2019},

  month        = {11}

}

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