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

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, andmore » 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.« less

Authors:
; ;  [1];  [2];  [3];  [4]
  1. TAPIR, Walter Burke Institute for Theoretical Physics, Mail code 350-17, California Institute of Technology, Pasadena, CA 91125 (United States)
  2. CCS-2, Los Alamos National Laboratory, P.O. Box 1663 Los Alamos, NM 87545 (United States)
  3. Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan)
  4. Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan)
Publication Date:
OSTI Identifier:
22679786
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 847; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; COMPUTERIZED SIMULATION; DISCRETE ORDINATE METHOD; DISTRIBUTION; DISTRIBUTION FUNCTIONS; ELASTIC SCATTERING; GRAVITATIONAL COLLAPSE; INTERACTIONS; MONTE CARLO METHOD; NEUTRINOS; NOISE; RADIANT HEAT TRANSFER; RADIATION TRANSPORT; RANDOMNESS; RELATIVISTIC RANGE; RELATIVITY THEORY; RESOLUTION; SPACE-TIME; SUPERNOVAE; VELOCITY

Citation Formats

Richers, Sherwood, Nagakura, Hiroki, Ott, Christian D., Dolence, Joshua, Sumiyoshi, Kohsuke, and Yamada, Shoichi, E-mail: srichers@tapir.caltech.edu. A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8BB2.
Richers, Sherwood, Nagakura, Hiroki, Ott, Christian D., Dolence, Joshua, Sumiyoshi, Kohsuke, & Yamada, Shoichi, E-mail: srichers@tapir.caltech.edu. A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae. United States. doi:10.3847/1538-4357/AA8BB2.
Richers, Sherwood, Nagakura, Hiroki, Ott, Christian D., Dolence, Joshua, Sumiyoshi, Kohsuke, and Yamada, Shoichi, E-mail: srichers@tapir.caltech.edu. Sun . "A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae". United States. doi:10.3847/1538-4357/AA8BB2.
@article{osti_22679786,
title = {A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae},
author = {Richers, Sherwood and Nagakura, Hiroki and Ott, Christian D. and Dolence, Joshua and Sumiyoshi, Kohsuke and Yamada, Shoichi, E-mail: srichers@tapir.caltech.edu},
abstractNote = {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.},
doi = {10.3847/1538-4357/AA8BB2},
journal = {Astrophysical Journal},
number = 2,
volume = 847,
place = {United States},
year = {Sun Oct 01 00:00:00 EDT 2017},
month = {Sun Oct 01 00:00:00 EDT 2017}
}