A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae

Sherwood Richers, Hiroki Nagakura, Christian D. Ott, Joshua Dolence, Kohsuke Sumiyoshi, Shoichi Yamada

    Research output: Contribution to journalArticle

    12 Citations (Scopus)

    Abstract

    The mechanism driving core-collapse supernovae is sensitive to the interplay between matter and neutrino radiation. However, neutrino radiation transport is very difficult to simulate, and several radiation transport methods of varying levels of approximation are available. We carefully compare for the first time in multiple spatial dimensions the discrete ordinates (DO) code of Nagakura, Yamada, and Sumiyoshi and the Monte Carlo (MC) code Sedonu, under the assumptions of a static fluid background, flat spacetime, elastic scattering, and full special relativity. We find remarkably good agreement in all spectral, angular, and fluid interaction quantities, lending confidence to both methods. The DO method excels in determining the heating and cooling rates in the optically thick region. The MC method predicts sharper angular features due to the effectively infinite angular resolution, but struggles to drive down noise in quantities where subtractive cancellation is prevalent, such as the net gain in the protoneutron star and off-diagonal components of the Eddington tensor. We also find that errors in the angular moments of the distribution functions induced by neglecting velocity dependence are subdominant to those from limited momentum-space resolution. We briefly compare directly computed second angular moments to those predicted by popular algebraic two-moment closures, and we find that the errors from the approximate closures are comparable to the difference between the DO and MC methods. Included in this work is an improved Sedonu code, which now implements a fully special relativistic, time-independent version of the grid-agnostic MC random walk approximation.

    Original languageEnglish
    Article numberaa8bb2
    JournalAstrophysical Journal
    Volume847
    Issue number2
    DOIs
    Publication statusPublished - 2017 Oct 1

    Fingerprint

    supernovae
    radiation transport
    neutrinos
    moments
    closures
    Monte Carlo method
    fluids
    angular resolution
    approximation
    random walk
    cancellation
    relativity
    confidence
    elastic scattering
    distribution functions
    grids
    tensors
    fluid
    momentum
    cooling

    Keywords

    • neutrinos
    • radiative transfer
    • supernovae: general

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae. / Richers, Sherwood; Nagakura, Hiroki; Ott, Christian D.; Dolence, Joshua; Sumiyoshi, Kohsuke; Yamada, Shoichi.

    In: Astrophysical Journal, Vol. 847, No. 2, aa8bb2, 01.10.2017.

    Research output: Contribution to journalArticle

    Richers, Sherwood ; Nagakura, Hiroki ; Ott, Christian D. ; Dolence, Joshua ; Sumiyoshi, Kohsuke ; Yamada, Shoichi. / A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae. In: Astrophysical Journal. 2017 ; Vol. 847, No. 2.
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